Patent Infringement In The UK: What You Need To Know

If you’re building a new product or process, the last thing you want is a surprise patent dispute derailing your launch.

Equally, if you’ve invested in R&D and secured a patent, you’ll want a clear plan for stopping copycats without overstepping the legal line.

This guide breaks down patent infringement under UK law in plain English and sets out practical steps to reduce risk, respond to letters, and enforce your rights with confidence.

What Counts As Patent Infringement In The UK?

In the UK, patent infringement is governed mainly by the Patents Act 1977. In simple terms, a granted UK patent gives its owner the exclusive right to the invention for up to 20 years (subject to renewal fees). If another business does certain restricted acts without permission, that can amount to infringement.

Restricted Acts For Product Patents

For a patented product, infringement can include:

• Making the product
• Offering it for sale or otherwise disposing of it
• Using it, importing it, or keeping it (for any of the above purposes)

Restricted Acts For Process (Method) Patents

For a patented process, infringement can include:

• Using the process or offering it for use
• Disposing of, offering to dispose of, using, importing or keeping a product obtained directly by that process

Do You Need To Intend To Infringe?

No. Infringement does not require bad faith. You can infringe a patent even if you didn’t know it existed. However, “innocent infringement” can sometimes reduce exposure to damages (for example, where you had no reason to know a patent existed). Marking products with “patent” and a number (or a web address identifying relevant patents) can strengthen an owner’s position on damages.

Common Defences And Exceptions

There are narrow exceptions and defences, including:

• Private, non‑commercial use
• Experimental use relating to the invention (e.g. certain R&D activities)
• Prior use (where you were already using the invention in good faith before the patent’s priority date)
• Repair of a patented product (as opposed to remaking it), which is a nuanced area

There are also disputes about whether a product or process actually “falls within the claims.” UK courts interpret patent claims purposively, and may consider equivalents when assessing infringement. In practice, this is a technical exercise-one of the many reasons getting specialist advice early is wise.

Where And Which Patents Apply?

The UK recognises UK national patents and UK designations of European patents granted by the European Patent Office. Since Brexit, the EU’s unitary patent system does not extend to the UK, and UK disputes proceed in UK courts. If you manufacture in one country and sell in another, you’ll need to consider where infringing acts occur and which patents are in force in those territories.

How To Reduce Your Risk Of Patent Infringement (Before You Launch)

Prevention is far cheaper than a dispute. If you’re preparing to launch a new product or process, build patent risk management into your development timeline.

1) Run A Freedom‑To‑Operate (FTO) Review

An FTO review is a practical search and analysis to identify in‑force patents that could block your product or method in key markets. It’s not the same as a patentability search (which checks if your innovation is new for filing your own patent). An FTO review helps you answer: “Can we sell this here without infringing someone else’s patent?”

• Scope your markets (UK first, then other target countries).
• Engage a patent professional to search active patents and interpret the claims against your design.
• Document the results and next steps.

If you need hands‑on help translating an FTO outcome into contracts and practical steps, speaking with an intellectual property lawyer who understands small business realities is a smart move.

2) Design‑Around Or Seek Permission

If your review flags risk, consider:

• Design‑around options to avoid patent claims
• Pausing features that are high‑risk while you iterate
• Negotiating a licence (or cross‑licence) so you can proceed legally

When a licence is the best route, make sure the terms cover scope (territory, field of use), royalties, reporting, improvements, sublicensing and termination. A properly drafted IP Licence will protect both parties and help you operate with confidence.

3) Lock Down Ownership Of Your Own IP

Even if you don’t plan to file a patent, ensure you own the IP in your product and documentation. With employees this is usually cleaner, but with freelancers and agencies you need express assignment.

• Use clear invention assignment clauses in employment agreements.
• With contractors, include a written IP Assignment so your business owns what you pay for.
• Be mindful of moral rights and background IP licensing.

If you engage independent contractors for R&D or prototyping, make ownership explicit from day one.

4) Use NDAs When Sharing Concepts

Before disclosing technical details, use a Non‑Disclosure Agreement. While an NDA is separate from patent rights, it helps you confidently explore manufacturer quotes, early testing or partnership discussions without giving away your competitive edge.

5) Consider Filing Your Own Patent Or Alternative Protection

If your product or process is new, inventive and industrially applicable, explore patent filing. Even a provisional filing can secure a priority date while you refine your design and fundraise. Complementary protection like registered designs and trade marks also matter-at minimum, secure your brand by moving to trade mark your logo so competitors can’t ride on your name.

What To Do If You Receive A Patent Infringement Letter

Opening a “letter before action” is confronting-don’t panic, and don’t ignore it. There are structured steps you can take to protect your position and keep options open.

1) Diarise Any Deadlines And Preserve Evidence

• Note response dates and any undertakings sought.
• Keep records: design history, lab notes, supplier communications, manufacturing changes, product samples, and your FTO analysis.

2) Avoid Admissions And Limit Communications

Don’t engage in casual back‑and‑forth or make statements that could be read as admissions. Route communications through your legal adviser. If you need to keep talking while you assess the claim, you can use a carefully worded reservation of rights letter to avoid waiving defences.

3) Assess The Patent And The Product

• Confirm the patent is granted, in force, and covers the UK.
• Review the claims against your current product or process (not just old prototypes).
• Check prosecution history and potential invalidity arguments (prior art, added matter, lack of sufficiency).

The UK IPO offers a non‑binding Opinions service on infringement and validity that can sometimes unlock pragmatic settlements.

4) Consider Practical Options

• Design adjustments that push you outside the claims
• Negotiating a licence or coexistence terms
• Seeking declarations of non‑infringement or revocation if you have strong grounds
• Agreeing interim steps (like pausing a feature) while negotiations continue

5) Be Careful With “Threats”

In the UK, unjustified threats of patent infringement proceedings can backfire under the Intellectual Property (Unjustified Threats) Act 2017. This means you need to take care with warning letters you send, and also evaluate whether the letter you received crosses the line (which can influence remedies). Professional guidance here is essential.

6) Check Your Insurance And Cashflow

IP legal expense insurance can help fund a defence or settlement. If you don’t have cover, forecast the cost of each route (design‑around vs licence vs litigation) and factor in disruption to your roadmap. Many disputes resolve commercially well before trial-your focus is choosing the route that protects your business and your runway.

Enforcing Your Own Patents Against Copycats

If you own a patent, a proactive and measured approach will give you the best chance of stopping infringement quickly and cost‑effectively.

Build A Monitoring Routine

• Track competitor announcements, marketplaces and trade shows.
• Set alerts for key technical terms and product names.
• Keep a docket of evidence (marketing claims, datasheets, teardown photos).

Start With Proportionate Steps

Consider a tiered approach: outreach call → carefully drafted letter (mindful of the unjustified threats regime) → negotiation for a licence or undertakings → court relief if needed (injunctions, damages or an account of profits, delivery‑up/destruction and costs). In urgent cases, interim injunctions may be available.

Mark Your Products

Marking products and webpages with patent details can support damages claims and deter potential infringers. Keep markings accurate and up to date to avoid misleading statements.

Use The Right Agreements

When you license your technology, use robust terms around confidentiality, quality control, improvements and audit rights. If software is involved, consider a Software Licence Agreement and EULA alongside your patent licence so usage rules are crystal clear.

Know The Remedies

UK courts can award injunctions to stop infringement, damages or an account of profits, and ancillary orders like disclosure and delivery‑up. Limitation periods typically run for six years from the infringing act. Many cases resolve through undertakings and commercial licences rather than full trials, so keep a settlement mindset if it achieves your commercial goals.

Key Contracts And Policies That Help Manage Patent Risk

Patent disputes don’t happen in a vacuum-your day‑to‑day contracts can dramatically reduce risk and give you leverage.

R&D And Manufacturing

• Non‑Disclosure Agreement: protect sensitive designs and test results before you share them with third parties.
• Development or Supply Agreements: clearly allocate foreground IP, background IP, improvements and ownership of tooling.
• Warranties and Indemnities: seek warranties that supplied components don’t infringe third‑party rights, and an indemnity where appropriate.

Employment And Contractors

• Employment Contracts: include invention and confidentiality clauses aligned with the Patents Act’s employee inventor rules.
• Contractor Agreements: ensure a written IP Assignment so your company owns what’s created.

Licensing And Collaboration

• Patent/Technology Licence: tailor scope, royalties, improvements, audit and termination. A well‑structured IP Licence helps avoid future disputes.
• Copyright And Know‑How: where documentation, drawings or training materials are shared, add a Copyright Licence Agreement to spell out permitted uses.

Brand And Related IP

While patents protect inventions, you should also lock down your brand and other IP around the product. Securing your brand by moving to trade mark your logo and your name gives you additional tools against look‑alike offerings, and reinforces your position in negotiations with competitors.

Governance And Practical Playbook

• Internal IP Policy: set rules for invention disclosure, lab notebooks, public disclosures and embargoes pre‑filing.
• Clear Decision Trees: who decides on FTO sign‑off, design changes, and when to seek external advice?
• Data Room Discipline: keep a clean, dated record trail-vital if you later need to prove dates or show prior designs.

When To Get Help

Patent issues get technical quickly. If you’re weighing a design‑around, a licence, or enforcement, speaking to an intellectual property lawyer early will usually save time and cost overall. Getting the right agreements in place upfront-your Non‑Disclosure Agreement, contractor IP terms, and licences-keeps your business protected from day one.

Key Takeaways

• Patent infringement in the UK covers making, selling, using, importing or keeping a patented product, and using a patented process or dealing in products obtained directly by that process.
• Mitigate risk before launch with a freedom‑to‑operate review, sensible design‑around choices, and-where needed-licences documented in a tailored IP Licence.
• Lock down ownership of your own innovations with express contractor terms and an IP Assignment, and use a Non‑Disclosure Agreement when sharing concepts externally.
• If you receive a patent infringement letter, don’t ignore it. Diarise deadlines, preserve evidence, limit communications, and assess the patent and your product with professional help-be mindful of unjustified threats rules when you respond.
• If you own a patent, mark your products, monitor the market, and take proportionate steps-many disputes resolve commercially via undertakings or licences without a courtroom fight.
• Complement patent strategy with brand protection-registering a trade mark for your name and logo strengthens your position in the market and in negotiations.

If you’d like help assessing patent infringement risk, drafting a licence, or responding to a letter, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no‑obligations chat. We’d be happy to help you protect your business and move forward with confidence.