One-Way NDA Letter UK: When to Use & What to Include

What this document is

A one-way confidentiality letter is a short, plain written agreement in letter form where one party, the recipient, promises to keep information shared by the other party, the discloser, confidential. The word 'one-way' matters here: only one side is sharing sensitive information, so only one side needs to sign up to confidentiality obligations.

Under English and Welsh contract law, once the recipient signs and returns it (or otherwise accepts the terms), it becomes a binding contract. The letter typically sets out what counts as confidential, what the recipient can and cannot do with the information, how long the obligations last, and what happens to the information when the discussions end.

It is shorter and less technical than a full non-disclosure agreement, but legally speaking it carries the same weight. Courts in England and Wales will generally enforce it provided the terms are clear and reasonable. It is commonly used in early-stage conversations, pitching to potential partners, or where a contractor needs access to internal information to quote for a job.

How to use this document

1. Identify the parties clearly. Set out the full legal name and address of both the disclosing party and the receiving party. If you are a limited company, include the registered company number. Getting the parties right matters because if a dispute arises later, you want no ambiguity about who promised what and who can enforce the obligations. 2. Define what counts as confidential information. Be specific enough that the recipient knows what they cannot share, but broad enough to capture the categories of information you expect to disclose. This might include technical data, financial figures, customer lists, business plans, designs, or know-how. A sensible definition covers information shared in writing, verbally, or visually, whether or not it is marked 'confidential' at the time. 3. Spell out the recipient's obligations. State that the recipient must keep the information secret, use it only for the agreed purpose (for example, evaluating a possible partnership), and not disclose it to third parties without written permission. You may also want to require them to limit internal access to staff who genuinely need to know, and to ensure those staff are bound by equivalent confidentiality duties. 4. Set a sensible time period. Decide how long the confidentiality obligations will last. For commercially sensitive information, two to five years is common, though genuine trade secrets may deserve longer. Avoid setting an indefinite period without good reason, a court may view an overly long or unlimited duration as unreasonable and decline to enforce it fully. 5. Cover return or destruction and signing. Include a clause requiring the recipient to return or destroy confidential materials when the discussions end or on request. Finish with signature blocks for both parties and a date. Once signed and exchanged, keep a copy safe, you may need to produce it if the recipient later breaches the terms and you need to take action.

Common questions