Confidentiality clause (UK): what you are agreeing to keep secret

A confidentiality clause is a promise to keep certain information secret, and not to use it for anything except the purpose it was shared for. In the UK it binds you two ways: as a term of the contract you signed, and through the separate equitable duty of confidence. The wording decides what counts as confidential and for how long.

Whether it appears inside an employment contract, a service agreement, or as a standalone NDA, the questions to ask are the same.

Key Takeaways

• A confidentiality clause binds you as a contract term and, on top of that, through the duty of confidence.
• The classic test comes from Coco v A N Clark: the information must have the necessary quality of confidence, be shared in circumstances implying secrecy, and be used without permission to the other side's detriment.
• The two things that decide how heavy the clause is are how widely it defines confidential information and how long the obligation lasts.
• No confidentiality clause or NDA can lawfully stop you whistleblowing, and since October 2025 it cannot stop a victim of crime speaking to the police or a support service.
• New rules voiding NDAs that cover workplace harassment and discrimination are law but not yet in force, and are expected to take effect in 2027.

What does a confidentiality clause do?

A confidentiality clause sets out what you must keep to yourself. You find it in most NDAs, in the "Confidentiality" section of an employment contract, and in service agreements where you will see a client's private information.

A typical clause has four moving parts:

• A definition of what counts as confidential information (this is the part that varies most).
• The obligation itself: not to disclose it, and often not to use it for anything beyond the agreed purpose.
• A duration, saying how long the obligation runs, sometimes indefinitely for genuine secrets.
• Carve-outs, listing what is not covered, such as information that is already public or that you already knew.

Because it often protects the same material as an IP assignment clause and sits close to a non-solicitation clause that protects client relationships, confidentiality is worth reading alongside both.

What a confidentiality clause means for you

The practical question is how much the clause actually restricts you, and for how long. A narrow, sensible clause protecting real secrets is standard and fine to sign. A sweeping one can follow you around for years.

Two things drive that. First, the definition: "all information relating to the business" is far wider than "the client list and pricing shared for this project". Second, the duration: a fixed term is normal, an indefinite gag over everything is not.

Take a hypothetical. You do a project for a startup and the NDA defines confidential information as "anything you learn about the company". Taken literally, that could stop you saying you ever worked with them. That is the kind of over-broad drafting worth tightening before you sign, and it is exactly what our deep dive on confidentiality clauses in UK contracts unpacks in more detail.

Is a confidentiality clause enforceable in the UK?

Usually, yes, if the information is genuinely confidential. Confidentiality is enforced two ways. The obvious one is as a contract term: you agreed to it, so breaking it is a breach of contract. The second is the equitable duty of confidence, which can protect confidential information even where the contract wording is imperfect.

The classic test comes from Coco v A N Clark (Engineers) Ltd [1969] RPC 41. For the duty to apply, three things must be true:

1. The information has the necessary quality of confidence, so it is not trivial or already public.
2. It was shared in circumstances importing an obligation of confidence, meaning both sides understood it was private.
3. It is used without authorisation to the detriment of the person who shared it.

There are hard limits worth knowing, and they are set by statute rather than by the clause.

A confidentiality clause or NDA cannot lawfully stop you making a protected disclosure, the legal term for whistleblowing. Section 43J of the Employment Rights Act 1996 makes any provision void so far as it tries to. Separately, since 1 October 2025, section 17 of the Victims and Prisoners Act 2024 makes an NDA void so far as it would stop a victim of crime disclosing information to the police, a qualified lawyer, a regulator, a victim support service or close family. That applies to agreements signed on or after that date, in England and Wales, and you do not need to have reported the crime for it to bite.

A third limit is coming but is not yet in force. The Employment Rights Act 2025 inserts a new section 202A into the Employment Rights Act 1996, which will void any provision in an agreement between an employer and a worker that stops the worker speaking about harassment or discrimination they experienced or witnessed at work. Certain "excepted agreements" will still allow confidentiality where the worker asks for it, with safeguards such as independent legal advice, and those conditions are being set in regulations. The Government consulted on them until 8 July 2026, with the rules expected to take effect in 2027 and not to apply retrospectively. If you are being asked to sign an NDA covering a harassment or discrimination complaint today, this is the direction of travel worth knowing about.

If you need to review one of these documents in full, our guide on how to review an NDA in the UK walks through it clause by clause.

Confidentiality clause: a fair version vs an aggressive one

The wider the definition and the longer the term, the heavier the clause. Neither on its own makes it unenforceable, but both are fair negotiation points.

What to push back on before you sign

• Narrow the definition. Ask for confidential information to be tied to specific categories or to what is shared for this project, not "everything".
• Add the standard carve-outs. Information that is already public, that you already knew, or that you develop independently should sit outside the clause.
• Cap the duration. A fixed term is normal for ordinary commercial information. Push back on an indefinite gag over everything.
• Make it mutual if you are sharing too. If you are handing over your own methods or materials, the clause should protect you as well.

If you are not sure whether an NDA or confidentiality clause is standard or unusually wide, upload it to Ookulli and it will flag which parts are normal and which are aggressive, with each point traced back to the UK law behind it.

This page is general information, not legal advice. The duty of confidence and the victims' NDA protection described here apply in England and Wales; Scotland and Northern Ireland differ, though the whistleblowing protection applies more widely. For a high-value or complex situation, speak to a qualified solicitor.