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Inventor guide

NDA Before Filing a Patent UK: Protecting Your Invention

UK inventors can lose patent rights if they disclose an invention publicly before filing. An NDA creates a legal obligation of confidence that prevents a pre-filing disclosure counting as prior art. This guide explains how to protect your idea the right way.

By Richard Wood, Founder9 min readUpdated 31 August 2026Last reviewed 31 August 2026inventionpatentIPUK law

You have invented something worth protecting. Before you can manufacture it, fund it, or bring in partners, you need to share it with other people. But sharing an invention before a patent is filed creates real legal risk: under UK and European patent law, a public disclosure before you file can destroy the novelty of your invention and bar you from ever obtaining patent protection. An NDA — signed before you share a single detail — is the legal tool that keeps that disclosure confidential and preserves your patent rights.

This is general information, not legal advice

NDASafe is a document preparation service, not a law firm. Our templates are legally reviewed against applicable UK law at the point of release, but every situation is different. Where significant value, unusual risk or a cross-border element is involved, take independent legal advice before you sign.

Why disclosure before filing matters: the novelty requirement

Under the UK Patents Act 1977, section 1(1)(a), an invention is patentable only if it is new — meaning it does not form part of the state of the art at the date of filing. The “state of the art” includes everything made available to the public anywhere in the world, in any form, before your filing date. If you describe your invention in a meeting, a pitch deck, a crowdfunding campaign, a tweet, or a technical paper before you file, that description enters the state of the art. Your own patent application can then be refused for lacking novelty.

This is a hard rule. There is no UK or European equivalent of the US 12-month grace period. Once the information is public, the damage is done. The only safe routes are: (a) file before you disclose to anyone, or (b) disclose only under a signed NDA so the disclosure remains confidential.

How an NDA preserves your patent position

A confidential disclosure is not a public disclosure. UK courts recognise that information shared under an obligation of confidence does not form part of the state of the art. The obligation of confidence can arise expressly (from a signed NDA) or impliedly (from the nature of the relationship), but an express obligation — a signed NDA — is by far the safer position.

A signed NDA puts this beyond doubt. It explicitly states that the information is confidential, sets out who the permitted recipients are, restricts the use to a specified purpose (for example, “to evaluate a potential commercial collaboration”), and gives you a legal remedy — injunction and damages — if the recipient breaches it.

The UK has no grace period — an NDA is not optional

In the US, inventors have 12 months after their own disclosure to file. In the UK and Europe, there is no grace period (outside very narrow exceptions). Any public disclosure before you file is potentially fatal to your patent. An NDA is not a bureaucratic precaution — it is the only way to share your invention before filing without risking your rights.

Which NDA to use and when

SituationNDA to useWhy
Sharing with a manufacturer to discuss productionOne-Way NDA (Disclosing) — £29You are disclosing; they receive. Binds them to confidence and restricts use to the evaluation purpose.
Sharing with an investor or business partnerOne-Way NDA (Disclosing) — £29Covers the pitch and due diligence stage. Limits the investor’s right to circumvent you.
Both sides will share confidential informationMutual NDA — £29If the manufacturer or partner also shares their own confidential processes with you, use a mutual NDA.
Engaging a contractor or designer to develop the inventionNDA with IP Assignment — £29The IP Assignment clause ensures all work product created by the contractor belongs to you. Critical before development work begins.
Hiring an employee to work on the projectEmployee NDA — £29Includes the mandatory whistleblowing carve-out. For R&D staff, also include an IP assignment in the employment contract.

What to do before you share anything

  1. Sign the NDA first, share details second. Never the other way around. An NDA signed after you have already described the invention in a meeting does not protect that earlier disclosure.
  2. Be specific about what is confidential. The NDA should describe the information being protected: “the design, engineering, and function of [Product Name], as described in the attached drawings and specification”.
  3. Limit the purpose. State why the recipient is being given the information: “solely for the purpose of evaluating a potential manufacturing agreement”.
  4. Do not email invention details before the NDA is returned signed. Email constitutes disclosure. If you send technical drawings on Monday and receive the signed NDA on Wednesday, the Monday email may be treated as a prior disclosure depending on the circumstances.
  5. Keep a record. Retain the signed NDA and note the date of signing. If you need to demonstrate that your pre-filing disclosures were all under NDA, you will need the documentary evidence.
  6. File as soon as possible. An NDA buys you time, but not indefinitely. The sooner you file, the safer your position. A UK patent application gives you a priority date immediately; the full specification can follow within 12 months.

What an NDA cannot do

  • An NDA is not a patent. It does not give you exclusive rights. If someone independently develops the same invention, an NDA does not stop them.
  • An NDA does not protect information that is already public. You cannot make public information confidential by asking someone to sign an NDA.
  • An NDA does not replace a patent attorney. For significant inventions, take advice from a UK-registered patent attorney (find one via the Chartered Institute of Patent Attorneys, cipa.org.uk).

IP Assignment: when your contractor will build the invention

A common scenario: you engage a mechanical engineer, a software developer, or a product designer to turn your concept into a working prototype. The NDA binds them to confidence — but it does not automatically transfer ownership of what they create. Under English law, copyright and design rights in work created by a contractor belong to the contractor, not the commissioning party, unless there is an assignment.

If the prototype, the software, the CAD drawings, or the manufacturing specifications could have commercial value, you need an IP Assignment clause that transfers ownership of those deliverables to you. The NDASafe NDA with IP Assignment combines both: the confidentiality obligation and the assignment of all work product.

Trade secrets protection in parallel

Your invention may also qualify as a trade secret under the Trade Secrets (Enforcement, etc.) Regulations 2018. A trade secret is information that is secret, has commercial value because it is secret, and has been subject to reasonable steps to keep it secret. If all three conditions are met, the law provides remedies against misappropriation even where there is no NDA — though an NDA is strong evidence that you took reasonable steps to maintain secrecy. Unlike a patent (20 years), trade secret protection continues as long as the information remains genuinely secret.

Protect your invention today with a UK NDA

The NDASafe One-Way NDA (Disclosing) and NDA with IP Assignment are drafted for England and Wales, reviewed against current UK law, and delivered instantly as an editable Word document. From £29. 14-day money-back guarantee.

Frequently asked questions

Can I share my invention idea without a patent if I have an NDA?

Yes, with important caveats. An NDA creates a legal obligation of confidence. A confidential disclosure does not count as prior art that destroys the novelty of your invention under UK patent law, provided the NDA is properly drafted and the recipient genuinely receives the information in confidence. However, an NDA is not a substitute for a patent: it does not give you exclusive rights to manufacture, sell, or license the invention. You should file a patent application as soon as you can; use an NDA to protect the period before you do.

Does the UK have a grace period for patent novelty like the US?

No. The US has a 12-month grace period under 35 USC 102(b)(1) that allows inventors to file up to a year after their own public disclosure. The UK and Europe have no equivalent grace period (other than for disclosures at officially recognised exhibitions or disclosures that were clear abuses of the applicant’s rights). Any public disclosure before you file a UK or European patent application can destroy novelty. A confidential disclosure under NDA is not a public disclosure, but an unprotected conversation, social media post, crowdfunding campaign or press article is.

What counts as a confidential disclosure for UK patent purposes?

A disclosure is confidential if the recipient knew, or ought to have known, that the information was secret and was being shared in circumstances importing an obligation of confidence. The clearest way to establish this is a signed NDA. Courts have also recognised implied confidentiality (for example, a disclosure between business partners exploring a joint venture), but an implied obligation is harder to prove and riskier to rely on. Always use a signed NDA.

Does an NDA protect my software idea the same way it protects a physical invention?

Yes, in terms of patent novelty. A confidential disclosure of software does not destroy the novelty of any patentable element of the software before you file. Note that software is only patentable in the UK as a computer-implemented invention where it produces a technical effect going beyond the normal physical interactions; purely abstract software logic is not patentable. However, an NDA also protects your source code, architecture, and algorithms as trade secrets and confidential information, independently of patent law.

Should I use an NDA with IP assignment or just a standard NDA?

Use a standard One-Way NDA (Disclosing) when you are sharing your invention with someone who is evaluating it or considering a commercial relationship, such as an investor, a potential manufacturer, or a licensing partner. Use an NDA with IP Assignment when you are engaging a contractor or developer to work on the invention itself: the IP Assignment clause ensures that anything they create in the course of the work belongs to you, not to them.

Templates mentioned in this guide