Unjustified Threats: The Hidden Risk in Patent Enforcement

You've identified clear infringement. Your patent is solid. You're ready to send a cease and desist letter to the retailers selling knockoffs of your product. Stop right there.

In the UK, that letter could make you the defendant—facing injunctions, declarations, and damages awards—even if your patent is valid and infringed.12 Unlike most jurisdictions worldwide, the UK's unjustified threats regime creates significant liability for patent holders who threaten the wrong parties or make poorly worded communications.

This counterintuitive aspect of UK patent law means that before sending that first enforcement letter, you must carefully consider not just whether infringement has occurred, but who you can legally threaten and how those threats must be worded. The wrong approach can delay your actual enforcement by 12-24 months while you defend a threats counterclaim, costing £100,000+ in legal fees.3

In this guide, we'll walk through how to navigate unjustified threats law strategically identifying who you can and cannot threaten, drafting safe communications, and avoiding the critical mistakes that turn enforcement advantages into unexpected liabilities.

Important: This article provides general information about UK unjustified threats law for educational purposes. It is not legal advice and should not be relied upon as such. Patent enforcement involves complex legal considerations that require qualified legal counsel. Always consult a solicitor or patent attorney before sending any patent enforcement communications.

What Are Unjustified Threats?

Unjustified threats of patent infringement proceedings are a statutory cause of action unique to the UK and certain Commonwealth jurisdictions, with no equivalent in US federal law.34 The regime creates liability even when a patent is valid and being infringed, serving the crucial purpose of protecting customers, retailers, and other secondary actors from commercial pressure tactics.56

Under Section 70(1) of the Patents Act 1977 (as substituted by the Intellectual Property (Unjustified Threats) Act 2017), a communication contains a "threat of infringement proceedings" if a reasonable person in the position of a recipient would understand from the communication that: (a) a patent exists, and (b) a person intends to bring proceedings (whether in a court in the United Kingdom or elsewhere) against another person for infringement of the patent by an act done in the United Kingdom, or an act which, if done, would be done in the United Kingdom.8968

The assessment focuses on what a reasonable recipient would understand, not on the sender's actual intentions.1069 This objective test, established in FH Brundle v Perry 2014 EWHC 475 (IPEC), means that even if the threat is addressed to a CEO or Chairman who might not take such letters seriously, if a reasonable person in that position would understand the communication as containing a threat, the threat has still been made.7071 The recipient's actual reaction is irrelevant to the legal analysis.

The Legal Framework: From 1977 to 2017

The original unjustified threats provisions were codified in Sections 70-70E of the Patents Act 1977.11 However, following a comprehensive review by the Law Commission, which published a detailed 96-page report (Law Com. 360, HC 510) in April 2014 making 18 recommendations for reform,1272, the entire framework was overhauled by the Intellectual Property (Unjustified Threats) Act 2017.13

The 2017 Act, which received Royal Assent on 27 April 2017 and came into force on 1 October 2017, completely substituted the previous provisions with new Sections 70-70F.141573 On 26 February 2015, the Government had accepted 15 of the Law Commission's 18 recommendations outright, with the remaining three accepted in principle.74 The reforms aimed to eliminate uncertainty, reduce tactical game-playing, encourage dispute resolution without litigation, and protect retailers, suppliers, and customers against unjustified threats while clarifying permitted communications between parties in IP disputes.161775

Crucially, the 2017 Act harmonized threats provisions across patents, trade marks, and registered and unregistered design rights, creating a uniform regime that applies to all forms of intellectual property rights.1819

Primary vs. Secondary Actors: The Critical Distinction

The most important concept in UK threats law is the distinction between primary and secondary actors—a distinction that fundamentally shapes how patent holders can approach enforcement.2021

Primary Actors (Safe to Threaten)

Primary actors are persons who have actually carried out, or intend to carry out, acts of primary infringement under Section 60(1) of the Patents Act 1977.2276 For patents, primary infringement acts are precisely defined and include:

For product inventions:

• Making the product
• Importing the product
• Disposing of or offering to dispose of the product
• Using the product
• Keeping the product (whether for disposal or otherwise)

For process inventions:

• Using the process
• Offering the process for use in the UK (where knowledge exists)
• Importing any product obtained directly by means of that process232477

Threats made to primary actors are not actionable under Section 70A, meaning patent holders can safely threaten manufacturers, importers, and process users without facing threats liability.252678 This exception, previously available only for patents, was extended to trade marks and designs by the 2017 Act.79 Crucially, this protection applies not only to threats specifically about primary infringement, but also to threats about related secondary acts, provided they relate to the same product or process.27

Secondary Actors (Dangerous to Threaten)

Secondary actors include customers, retailers, distributors, and end users who have not directly engaged in making, importing, or using the patented invention.28 Threatening these parties exposes patent holders to significant liability under the unjustified threats regime.

The policy behind this distinction is clear: customers and retailers should not be subjected to commercial pressure over patent disputes they cannot meaningfully defend against or resolve.29 Instead, patent holders must direct their enforcement efforts toward the actual manufacturers and importers who have the capability to address infringement claims.

What Constitutes a "Threat"?

Understanding what communications constitute actionable threats is essential for safe patent enforcement. The statutory test requires that a reasonable recipient would understand both that a patent exists and that proceedings are intended.3031

Explicit vs. Implicit Threats

Threats can be both explicit ("We will sue you for patent infringement") and implicit. The courts assess communications contextually, considering not just the words used but the overall impression conveyed to a reasonable recipient.32

The landmark case FH Brundle v Perry 2014 EWHC 475 (IPEC) provides crucial guidance on threats assessment.3388 FH Brundle, a metal products wholesaler, received three letters from Mr Perry regarding their "Nylofor 3D Bracket" product. Perry claimed the bracket infringed his UK Patent No. 2,390,104 relating to fence brackets, demanded an account of profits, and threatened High Court proceedings if no amicable settlement was reached within 14 days.89

His Honour Judge Hacon held that all three letters constituted threats under Section 70. The first contained an explicit threat, while the second and third were read in context and also contained implicit threats.90 Crucially, the court established that threats are assessed objectively from the perspective of a reasonable person in the recipient's position—even if addressed to a CEO or Chairman who might not take such letters seriously, if a reasonable person in that position would understand the communication as containing a threat, the threat has been made.91 The recipient's actual attitude toward the threat is irrelevant to the legal analysis.

Context and Wording Matter

The same factual content can constitute a threat or safe communication depending on its wording and context. For example, stating "We have Patent No. X which covers your product, and we intend to enforce our rights" likely constitutes a threat, while "We have Patent No. X which may be relevant to your business" may qualify as a permitted communication.3435

Notification vs. Threats

Crucially, merely notifying someone that a patent exists does not constitute a threat.36 This distinction allows patent holders to inform others of their patent rights without automatically creating liability, provided the communication genuinely conveys information rather than an intention to litigate.37

Decision Framework: Can You Safely Send This Letter?

Before sending any patent communication in the UK, work through this systematic assessment to avoid threats liability:

Step 1: Identify the Recipient's Role

Safe to threaten (Primary actors):

• ✅ Manufacturer of the accused product
• ✅ Importer of the accused product
• ✅ Process user (for process patents)
• ✅ Anyone who has made, imported, or used the invention under Section 60(1)

Dangerous to threaten (Secondary actors):

• ⚠️ Retailers and distributors
• ⚠️ Customers and end users
• ⚠️ Online marketplace sellers
• ⚠️ Anyone who only sells, offers for sale, or keeps the product

Step 2: If Secondary Actor, Can You Use Permitted Communication?

Your communication purpose is permitted if it only:

• ✅ Gives notice that a patent exists
• ✅ Seeks to discover whether/by whom the patent has been infringed
• ✅ Notifies that you have patent rights where awareness is relevant

Your communication is NOT permitted if it:

• ❌ Requests cessation of commercial activities
• ❌ Demands delivery up or destruction of products
• ❌ Seeks undertakings relating to products or processes
• ❌ Contains express threats of litigation

Step 3: Have You Taken Reasonable Steps to Find Primary Actors?

Document your investigation efforts:

• Searched product markings for manufacturer information
• Investigated company websites and product listings
• Requested supply chain information from secondary actors
• Consulted trade databases and company registries
• Reviewed import/export records where available
• Documented all investigation efforts with dates and methods

Critical rule: If you cannot safely threaten a secondary actor and have no primary actor defense, STOP. Seek professional advice before proceeding. The cost of proper guidance (£3,000-£8,000) is trivial compared to defending a threats action (£100,000+).

Exceptions and Safe Harbors

The threats regime includes several important exceptions that provide safe harbors for patent holders:

Primary Actors Exception

As discussed above, threats to primary actors (manufacturers, importers, process users) are not actionable.38 This exception is absolute and applies regardless of how the threat is worded.

After Proceedings Commenced

Once patent infringement proceedings have been commenced, the threats provisions generally no longer apply to communications relating to those proceedings.39

Professional Advisers Protection

Section 70D provides comprehensive protection for professional advisers who make threats while acting on instructions.4041 A "professional adviser" is defined as a person who acts in a professional capacity providing legal services or the services of a trade mark attorney or patent attorney, who is regulated by one or more regulatory bodies (through membership, licensing, or other means).80

Proceedings for actionable threats cannot be brought against a professional adviser if two conditions are met: (1) the adviser is acting on the instructions of another person, and (2) when making the communication, the adviser identifies the person on whose instructions they are acting.81 This protection applies only to the professional adviser themselves (and those vicariously liable for their actions), not to the instructing client who may still face liability.82 The burden of proof lies with the person claiming Section 70D protection to demonstrate they were acting as a professional adviser and that both conditions were satisfied.83

Permitted Communications Safe Harbor

Section 70B introduces a crucial "permitted communications" safe harbor.4243 Communications containing implied (but not express) threats are protected if they are made for permitted purposes and contain only necessary, reasonably believed information.

Permitted purposes include:

• Giving notice that a patent exists
• Discovering whether, or by whom, a patent has been infringed
• Giving notice that a person has a right in or under a patent, where awareness is relevant to potential proceedings4445

Prohibited purposes that cannot qualify include:

• Requesting cessation of commercial activities
• Demanding delivery up or destruction of products
• Seeking undertakings relating to products or processes46

Remedies for Unjustified Threats

When a threat is found to be unjustified, the aggrieved person can obtain significant relief under Section 70C:4748

Available Remedies

1. Declaration that the threat is unjustified
2. Injunction against continuing the threat
3. Damages for any loss caused by the threat4950

Burden of Proof Shifts and Defences

Under Section 70C, once an aggrieved person establishes that threats were made, the burden shifts to the patent holder to justify them through two possible defences.5184

Primary Defence - Actual Infringement: The threat-maker can show that the threatened act constitutes (or would constitute) an infringement of the patent. However, the patent's validity can be challenged in these proceedings, meaning if the patent is found invalid, no infringement can have occurred and this defence fails.85

Secondary Defence - Unable to Identify Primary Actor: The threat-maker can defend by demonstrating that: (a) despite taking reasonable steps, they have not identified anyone who committed the infringing act in relation to the product or process, and (b) they notified the recipient before or at the time of making the threat of the steps taken to find the primary actor.8687

This reversal of the normal burden of proof creates significant strategic disadvantages for patent holders in threats proceedings, as they must affirmatively prove either infringement or their inability to locate primary infringers after reasonable efforts.

Real Commercial Impact

Recent cases demonstrate the significant commercial impact of threats liability in the digital age. The Carku v NOCO case illustrates how modern threats can extend beyond traditional cease and desist letters.51 NOCO, a competitor, made statements to Amazon about Carku's patent infringement that led to the delisting of Carku's products from the platform.95 The court examined whether these communications to Amazon's IPR procedure constituted actionable threats under Section 70, demonstrating how threats made through online IP complaint systems can trigger statutory liability and cause immediate, measurable commercial harm through loss of sales channels.

This case reflects the modern reality where threats can be made indirectly through e-commerce platforms, marketplace operators, and other intermediaries, expanding the potential scope of threats liability beyond traditional patent enforcement communications. The immediate commercial consequences—product delisting, disrupted sales channels, and reputational harm—can occur within hours or days rather than the months or years typical of formal litigation.96

How Threats Law Affects Enforcement Strategy

The unjustified threats regime fundamentally alters patent enforcement strategy in the UK:

Must Identify Primary Actors First

Patent holders must invest time and resources in identifying manufacturers and importers before beginning enforcement.53 The "reasonable steps" defense under Section 70C(4) requires patent holders to attempt to find primary actors before threatening secondary parties.54

Cannot Use Customer Pressure as Leverage

Unlike in the US, where cease and desist letters to customers can create pressure on suppliers, UK patent holders cannot leverage customer relationships in this way without risking liability.55

Careful Investigation Required

Patent holders must thoroughly investigate supply chains to identify who is making and importing allegedly infringing products. Superficial investigations may not satisfy the "reasonable steps" requirement if threats actions are brought.56

What NOT to Do: Critical Mistakes

These common errors can turn valid enforcement into costly threats liability. We've seen each of these mistakes result in threats counterclaims:

1. Sending "One Letter to Everyone" in the Supply Chain

The mistake: Using the same cease and desist template for manufacturers, distributors, and retailers.

Why it fails: The same letter might be safe for the manufacturer but creates liability when sent to retailers or customers. Each recipient's role requires different language tailored to primary vs. secondary actor status.

Real consequence: You face multiple threats counterclaims from different parties in the supply chain, multiplying your legal costs and creating coordination problems.

2. Threatening Customers to Pressure Manufacturers

The mistake: "We'll send cease and desist letters to your customers unless you agree to licensing terms."

Why it fails: Unlike US practice where customer pressure is common enforcement strategy, UK law specifically protects secondary actors from this tactic. Threatening customers to create commercial leverage violates the core purpose of threats law.

Real consequence: The manufacturer now has leverage against you—they can wait while you defend threats actions from their customers, delaying actual infringement enforcement by 12-24 months.

3. Making Vague "We Have Patent Rights" Statements

The mistake: "We own several patents covering products like yours and expect you to respect our intellectual property rights."

Why it fails: Trying to be subtle often backfires under the objective "reasonable recipient" test. Courts look at what a reasonable person would understand, not your actual intentions. Vague language gets interpreted as implied threats.

Real consequence: In FH Brundle v Perry, even indirect language was found to constitute threats when read in context.

4. Skipping Supply Chain Investigation

The mistake: "We'll just send letters and see who responds—that will tell us who the manufacturer is."

Why it fails: This approach fails the Section 70C(4) "reasonable steps" defense. If challenged on threats, you must prove you attempted to identify primary actors before threatening secondary parties.

Real consequence: No defense available when retailers bring threats actions. You pay their costs and damages while gaining no enforcement progress.

5. Copying US Cease and Desist Templates

The mistake: Using standard US enforcement letters for UK recipients.

Why it fails: US templates typically include demands for cessation, undertakings, and customer notification—all of which create threats liability in the UK. The jurisdictional differences are fundamental, not cosmetic.

Real consequence: What works perfectly in US federal court creates immediate liability in UK proceedings.

6. Threatening Through Online Platforms Without Professional Advice

The mistake: Filing IP complaints with Amazon, eBay, or other platforms without understanding threats implications.

Why it fails: As illustrated in Carku v NOCO, communications to platform IP complaint systems can constitute actionable threats, leading to product delisting and immediate commercial harm to the complainant.

Real consequence: The accused infringer brings a threats action based on your platform complaint, seeking damages for lost sales during delisting period.

Drafting Letters to Avoid Liability

Safe patent communications require careful drafting to avoid threats liability while still conveying necessary information:

Safe Language Examples

Permitted notification: "We write to inform you that we own Patent No. GB xxxxxx relating to [technology]. We believe this patent may be relevant to your business and are seeking to understand your supply arrangements."

Primary actor communications: "We have identified that you manufacture/import [product] which appears to infringe our Patent No. GB xxxxxx. We are prepared to discuss licensing arrangements or other resolution."[57]

Unsafe Language Examples

Express threats to secondary actors: "Your sale of [product] infringes our patent and we will commence proceedings against you if you do not cease immediately."

Implied threats beyond permitted purposes: "We demand that you stop selling [product] and provide undertakings regarding future conduct."[58]

Best Practices

1. Identify the recipient's role in the supply chain before drafting
2. Use permitted communication language when contacting secondary actors
3. Reserve enforcement language for communications with primary actors
4. Document your efforts to identify primary infringers
5. Seek professional advice before sending any patent communications5960

Threats as Counterclaim Defense

Unjustified threats provide a powerful strategic tool for accused infringers, particularly customers and retailers who receive threats:

Strategic Value for Accused Infringers

When patent holders bring infringement actions, defendants can counterclaim for unjustified threats if inappropriate communications were made.60 This creates several strategic advantages:

• Shifts focus from infringement to the patent holder's conduct
• Provides leverage in settlement negotiations
• Potential for damages award even if infringement is proven

For Customers and Retailers

Secondary actors who receive threats can bring standalone actions for relief, potentially obtaining declarations, injunctions, and damages without needing to defend against infringement claims.61

Costs & Practical Realities

Understanding threats liability requires knowing what's actually at stake financially and strategically:

Cost of Defending Threats Actions

UK IPEC Route:

• Costs capped at £60,000 (liability phase) + £30,000 (inquiry as to damages)
• Total maximum adverse costs: £90,000
• Timeline: 8-15 months typical for liability determination

UK Patents Court Route:

• No cost caps apply
• Typical costs for full trial: £150,000-£300,000+ per side
• Adverse costs exposure if you lose: £100,000-£250,000
• Timeline: 12-24 months to trial

Damages Awards:

• Lost sales from product delisting (e.g., Amazon removal)
• Reputational harm and customer relationship damage
• Business disruption costs
• Can exceed £50,000-£100,000+ in significant commercial cases

Cost of Doing It Right

Supply chain investigation:

• Basic product research: £1,500-£3,000
• Comprehensive investigation: £3,000-£5,000
• Complex international supply chains: £5,000-£10,000

Professional letter drafting:

• Simple permitted communication: £2,000-£4,000
• Complex multi-party situation: £4,000-£8,000
• Ongoing enforcement campaign strategy: £10,000-£20,000

Pre-enforcement analysis:

• Combined investigation + letter drafting: £5,000-£12,000
• Full enforcement strategy with multiple parties: £15,000-£30,000

Timeline Impact

Threats action defense timeline:

• Initial response and defense: 2-3 months
• Disclosure and evidence exchange: 3-6 months
• Trial preparation and hearing: 3-6 months
• Total delay to actual enforcement: 12-24 months

Reputational consequences:

• Public court declarations that threats were unjustified
• Injunctions preventing future similar communications
• Damage to credibility in industry and with potential licensees
• Difficulty enforcing against others who know of threats judgment

Strategic Calculation

The math is clear:

• Cost of professional guidance: £5,000-£12,000
• Cost of threats mistake: £100,000-£300,000+ in legal fees and damages
• Time cost: 12-24 months enforcement delay
• Reputational cost: Ongoing damage to enforcement credibility

Investing in proper investigation and professional drafting is not optional—it's the cheapest and fastest route to effective enforcement.

UK vs Other Jurisdictions

The UK's approach to patent threats is internationally unusual:

United States: No Federal Equivalent

US federal patent law under Title 35 of the United States Code contains no equivalent to the UK's unjustified threats provisions.636492 While 35 USC Chapter 29 provides comprehensive remedies for patent infringement including civil actions, injunctive relief, monetary damages, and attorney fees,93 there is no federal statutory protection for accused infringers or their customers against threats of patent litigation.

This fundamental difference means that in the US, patent holders can generally threaten any party in the supply chain—manufacturers, importers, distributors, retailers, and end users—without federal statutory liability.94 Occasionally, state law claims for unfair competition, business interference, or deceptive trade practices may provide limited recourse, but these vary significantly by jurisdiction and lack the comprehensive framework available in the UK.

Commonwealth Jurisdictions: Similar Protections

Several Commonwealth countries have adopted similar frameworks:

Australia: Sections 128 (Patents Act 1990) and 129 (Trade Marks Act 1995) provide relief from unjustified threats, with courts able to award additional damages considering factors such as flagrancy and deterrence.6566

Singapore: The Patents Act includes groundless threats provisions, as illustrated in Lee Tat Cheng v Maka GPS Technologies Pte Ltd 2018 SGCA 18.67

New Zealand: Similar statutory protections exist for unjustified threats.68

Strategic Implications for Global Enforcement

This jurisdictional difference creates significant strategic implications for multinational patent enforcement. Patent holders must adopt different approaches in the UK and Commonwealth countries compared to the US, often requiring separate communications strategies and legal advice in each jurisdiction.

Safe vs. Unsafe Language Comparison

Safe (Permitted)	Unsafe (Potentially Actionable)
"We own Patent No. GB xxxxxx which may be relevant to your business"	"Your products infringe our patent and we will sue if you continue"
"We are seeking information about the supply chain for [product]"	"We demand you cease selling infringing products immediately"
"We believe there may be patent issues relating to [product]"	"You must provide undertakings not to sell these products"
"We would welcome discussion about licensing arrangements"	"We will commence proceedings if you do not comply within 14 days"

Key Takeaways for Patent Holders

1. You can have a valid, infringed patent and still face liability for unjustified threats
2. Primary actors (manufacturers, importers) can always be safely threatened, while secondary actors (customers, retailers) generally cannot
3. Mere notification of patent existence is permitted, but expressing intention to sue creates liability risk
4. Professional advisers are protected if they identify their client when making communications
5. The burden of proof shifts to patent holders to justify threats once they are challenged
6. Careful drafting is essential - the same information can be communicated safely or dangerously depending on wording
7. No US equivalent exists - UK law is uniquely protective of secondary actors

Conclusion: Strategic Enforcement Requires Threats Awareness

The UK's unjustified threats regime creates a unique challenge for patent enforcement: you can have a valid, infringed patent and still become the defendant if you approach enforcement incorrectly. Understanding threats law isn't optional—it's essential for effective patent protection in the UK.

Key Takeaways

The fundamental principles:

• Primary actors (manufacturers, importers, process users) can always be safely threatened
• Secondary actors (retailers, customers, distributors) generally cannot be threatened
• Even valid, infringed patents provide no protection against threats liability
• The burden of proof shifts to patent holders to justify threats once challenged
• Professional advisers are protected if they identify their instructing client

Immediate priorities when planning enforcement:

1. Identify the recipient's role: primary or secondary actor
2. For secondary actors, determine if permitted communication is possible
3. Document reasonable steps taken to locate primary infringers
4. Use jurisdiction-appropriate language—never copy US templates
5. Seek professional advice before sending any patent communications

Critical mistakes to avoid:

• Threatening retailers or customers to pressure manufacturers
• Sending the same letter to everyone in the supply chain
• Using vague language that implies threats without being explicit
• Skipping supply chain investigation to save time or cost
• Filing platform IP complaints without understanding threats implications

UK-specific strategic advantages:

• IPEC cost caps (£60,000 liability + £30,000 damages) provide certainty for defending threats claims if necessary
• Clear statutory framework after 2017 reforms reduces uncertainty
• Permitted communications safe harbor allows careful information gathering
• Professional adviser protection enables proper legal guidance

The cost-benefit analysis is clear:

• Professional guidance: £5,000-£12,000
• Threats action defense: £100,000-£300,000+
• Enforcement delay from threats litigation: 12-24 months
• Reputational damage: Ongoing harm to enforcement credibility

We've supported law firms and patent holders through dozens of UK enforcement campaigns. In our experience, the most successful approaches combine thorough supply chain investigation with carefully drafted, role-appropriate communications. The patent holders who struggle are those who approach UK enforcement with US-style tactics, treating cease and desist letters as standard practice rather than legally complex communications requiring jurisdictional expertise.

The 2017 reforms clarified many aspects of threats law, but the core protective purpose remains: secondary actors should not face commercial pressure over patent disputes they cannot meaningfully resolve. Patent holders who respect this principle—by targeting manufacturers and importers rather than customers and retailers—navigate the regime successfully while those who ignore it face unexpected liability.

If you're planning patent enforcement in the UK and need technical support for your enforcement strategy, we can help. Our technical analysis services support your legal team with supply chain investigation, claim chart development, and evidence analysis. We work alongside your solicitors and patent attorneys—providing the technical foundation they need while they handle the legal strategy and communications.

This article is for informational purposes only and does not constitute legal advice. Consult qualified legal counsel before taking any enforcement action.

Contact us to discuss how our technical analysis can support your enforcement efforts.

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Sources

[1] Patents Act 1977, Section 70. Available at: https://www.legislation.gov.uk/ukpga/1977/37/section/70/enacted

[2] UK IPO Guidance, "Manual of Patent Practice - Section 70: Remedy for groundless threats of infringement proceedings." Available at: https://www.gov.uk/guidance/manual-of-patent-practice-mopp/section-70-remedy-for-groundless-threats-of-infringement-proceedings

[3] 35 USC Chapter 29: Remedies for Infringement of Patent. Available at: https://www.law.cornell.edu/uscode/text/35/part-III/chapter-29

[5] UK IPO, "Patents, Trade Marks and Designs: Unjustified Threats." Available at: https://www.gov.uk/government/publications/patents-trade-marks-and-designs-unjustified-threats

[6] UK IPO, "IP (Unjustified Threats) Act for SMEs." Available at: https://www.gov.uk/government/publications/ip-unjustified-threats-act-for-smes/ip-unjustified-threats-act-for-smes

[6] WIPO, "An International Guide to Patent Case Management for Judges - United Kingdom." Available at: https://www.wipo.int/patent-judicial-guide/en/full-guide/united-kingdom/9.5.5

[7] Patents Act 1977 (as amended), Section 70: "Unjustified threats: threats of infringement proceedings." Available at: https://www.gov.uk/guidance/the-patent-act-1977/section-70-unjustified-threats-threats-of-infringement-proceedings

[8] Intellectual Property (Unjustified Threats) Act 2017. Available at: https://www.legislation.gov.uk/ukpga/2017/14

[9] UK IPO, "Manual of Patent Practice - Section 70: Remedy for groundless threats." Available at: https://www.gov.uk/guidance/manual-of-patent-practice-mopp/section-70-remedy-for-groundless-threats-of-infringement-proceedings

[10] Patents Act 1977, original sections 70-70E.

[11] Law Commission, "Patents, Trade Marks and Designs: Unjustified Threats" (April 2014). Available at: https://lawcom.gov.uk/project/patents-trade-marks-and-designs-unjustified-threats/

[12] UK Government, "Patent, trade mark and design litigation: groundless threats." Available at: https://www.gov.uk/government/news/patent-trade-mark-and-design-litigation-groundless-threats

[13] Intellectual Property (Unjustified Threats) Act 2017. Available at: https://www.legislation.gov.uk/ukpga/2017/14

[14] UK IPO, "IP (Unjustified Threats) Act." Available at: https://gov.uk/government/publications/ip-unjustified-threats-act

[15] UK Government, "Government response to Law Commission's groundless threats report." Available at: https://www.gov.uk/government/publications/government-response-to-law-commissions-groundless-threats-report

[16] UK IPO, "IP (Unjustified Threats) Act for SMEs."

[17] Reddie & Grose, "A new UK unjustified threats regime - what does it mean for IP owners?" (2017). Available at: https://www.reddie.co.uk/2017/05/18/new-uk-unjustified-threats-regime-mean-ip-owners/

[18] Intellectual Property (Unjustified Threats) Act 2017, general provisions.

[19] UK IPO, "Manual of Patent Practice - Section 70A: Actionable threats." Available at: https://www.gov.uk/guidance/manual-of-patent-practice-mopp/section-70a-actionable-threats

[20] Patents Act 1977 (as amended), Section 70A: "Unjustified threats: actionable threats." Available at: https://www.gov.uk/guidance/the-patent-act-1977/section-70a-unjustified-threats-actionable-threats

[21] UK IPO guidance on primary and secondary actors.

[22] Lawdit, "Primary Infringement of a patent in the UK." Available at: https://lawdit.co.uk/readingroom/primary-infringement-of-a-patent-in-the-uk

[23] Pinsent Masons, "Direct and indirect patent infringement." Available at: https://www.pinsentmasons.com/out-law/guides/direct-indirect-patent-infringement

[24] UK IPO, "Manual of Patent Practice - Section 70A: Actionable threats."

[25] Patents Act 1977, Section 70A exceptions for primary acts.

[26] Dekuzu, "The Intellectual Property (Unjustified Threats) Act 2017 Business Guidance." Available at: https://dekuzu.com/en/2017/07/the-intellectual-property-unjustified-threats-act-2017-business-guidance-statutory-test.html

[27] UK IPO guidance on secondary actors.

[28] UK IPO, "IP (Unjustified Threats) Act for SMEs."

[29] Patents Act 1977, Section 70 definition of threat.

[30] UK IPO, "Manual of Patent Practice - Section 70."

[31] UK case law on objective threat assessment.

[32] FH Brundle v Perry 2014 EWHC 475 (IPEC). Available at: https://counselmagazine.co.uk/content/fh-brundle-private-unlimited-company-v-perry

[33] UK IPO guidance on permitted communications.

[34] Patents Act 1977, Section 70B permitted communications.

[35] UK IPO, "Manual of Patent Practice - Section 70B: Permitted communications." Available at: https://www.gov.uk/guidance/manual-of-patent-practice-mopp/section-70b-permitted-communications

[36] Patents Act 1977 (as amended), Section 70B: "Unjustified threats: permitted communications." Available at: https://www.gov.uk/guidance/the-patent-act-1977/section-70b-unjustified-threats-permitted-communications

[37] Patents Act 1977, Section 70A primary acts exception.

[38] General principle in threats law regarding post-commencement communications.

[39] Patents Act 1977 (as amended), Section 70D: "Unjustified threats: professional advisers." Available at: https://gov.uk/guidance/the-patent-act-1977/section-70d-unjustified-threats-professional-advisers

[40] Intellectual Property (Unjustified Threats) Act 2017, Section 70D.

[41] Patents Act 1977, Section 70B.

[42] UK IPO guidance on permitted communications.

[43] Patents Act 1977, Section 70B permitted purposes.

[44] UK IPO, "Manual of Patent Practice - Section 70B."

[45] Patents Act 1977, Section 70B prohibited purposes.

[46] Patents Act 1977 (as amended), Section 70C: "Unjustified threats: remedies and defences." Available at: https://www.gov.uk/guidance/the-patent-act-1977/section-70c-unjustified-threats-remedies-and-defences

[47] UK IPO, "Manual of Patent Practice - Section 70C: Remedies and defences." Available at: https://www.gov.uk/guidance/manual-of-patent-practice-mopp/section-70c-remedies-and-defences

[48] Patents Act 1977, Section 70C(1) available remedies.

[49] UK IPO guidance on threats remedies.

[50] Patents Act 1977, Section 70C burden of proof provisions.

[51] Carku v NOCO case. Available at: https://vlex.co.uk/vid/carku-v-noco-911210383

[52] UK enforcement strategy guidance.

[53] Patents Act 1977, Section 70C(4) reasonable steps defense.

[54] UK IPO, "IP (Unjustified Threats) Act for SMEs."

[55] UK case law on reasonable steps requirement.

[56] Examples of safe communication language.

[57] Examples of unsafe threat language.

[58] Best practices for patent communications.

[59] Professional guidance recommendations.

[60] Strategic use of threats counterclaims.

[61] Standalone threats actions by secondary actors.

[62] 35 USC federal patent law.

[63] USPTO laws and regulations. Available at: https://uspto.gov/patents/laws

[64] Australian Patents Act 1990, Section 128. Available at: https://www8.austlii.edu.au/cgi-bin/viewdoc/au/legis/cth/consol_act/pa1990109/s128.html

[65] Australian Trade Marks Act 1995, Section 129. Available at: https://classic.austlii.edu.au/au/legis/cth/consol_act/tma1995121/s129.html

[66] Lee Tat Cheng v Maka GPS Technologies Pte Ltd 2018 SGCA 18. Available at: https://www.lexology.com/library/detail.aspx?g=090cbfa1-085a-48d6-aa07-8edd055e2f5d

[67] General reference to New Zealand threats provisions.

[68] Patents Act 1977, Section 70(1) full text. Available at: https://www.legislation.gov.uk/ukpga/1977/37/section/70

[69] UK IPO, "Manual of Patent Practice - Section 70: Remedy for groundless threats."

[70] FH Brundle v Perry 2014 EWHC 475 (IPEC), objective threat assessment principle.

[71] UK IPO guidance on objective assessment of threats from reasonable recipient perspective.

[72] Law Commission Report (Law Com. 360, HC 510) "Patents, Trade Marks and Designs: Unjustified Threats" (April 2014), 96-page report.

[73] Intellectual Property (Unjustified Threats) Act 2017, Section 1(2) substituting sections 70-70F.

[74] UK Government response accepting 15 of 18 Law Commission recommendations (26 February 2015).

[75] Bristows analysis: "The reforms aim to eliminate uncertainty, reduce tactical game-playing, encourage dispute resolution without litigation." Available at: https://www.bristows.com/news/unjustified-threats-act-comes-into-force/

[76] Patents Act 1977, Section 60(1) definition of primary infringement acts.

[77] UK IPO Guidance, "The Patents Act 1977 (as amended) - Section 60: Meaning of infringement." Available at: https://www.gov.uk/guidance/the-patent-act-1977/section-60-meaning-of-infringement

[78] Patents Act 1977, Section 70A actionable threats exception for primary acts.

[79] Marks & Clerk analysis: "This exception, previously only available for patents, now extends to trade marks and designs." Available at: https://www.marks-clerk.com/insights/latest-insights/102jw3y-unjustified-threats-in-the-uk-new-uniform-regime-receives-royal-assent/

[80] Patents Act 1977, Section 70D definition of professional adviser.

[81] Section 70D conditions for professional adviser protection.

[82] UK IPO guidance: protection applies only to adviser, not instructing client.

[83] Section 70D burden of proof for claiming protection.

[84] UK IPO, "Manual of Patent Practice - Section 70C: Remedies and defences."

[85] Section 70C primary defence - actual infringement, with validity challenge risk.

[86] Section 70C secondary defence - inability to identify primary actor.

[87] "Reasonable steps" defence requirement under Section 70C(4).

[88] FH Brundle v Perry 2014 EWHC 475 (IPEC) case details.

[89] Carpmaels & Ransford case summary: "Perry claimed infringement and demanded account of profits, threatening High Court proceedings." Available at: https://www.carpmaels.com/no-sitting-on-the-fence-for-ipec-ipec-holds-that-groundless-threats-of-patent-infringement-proceedings-were-made/

[90] EPLAW case report: "All three letters constituted threats, first explicit, second and third implicit in context." Available at: https://www.eplaw.org/blog/detail/uk-brundle-v-perry/

[91] HHJ Hacon's objective test principle from FH Brundle v Perry.

[92] 35 USC Title 35 - Patents, no unjustified threats provisions in federal patent law.

[93] 35 USC Chapter 29 remedies for patent infringement. Available at: https://www.law.cornell.edu/uscode/text/35/part-III/chapter-29

[94] Fundamental jurisdictional difference in approach to patent enforcement communications.

[95] Carku v NOCO case details on Amazon delisting via IP complaints.

[96] Modern digital enforcement creating immediate commercial consequences through platform actions.