A one-way (unilateral) NDA protects confidential information flowing in one direction — one party discloses, the other must keep it secret. A mutual (bilateral) NDA protects information flowing both ways, because both parties will share confidential information. The right choice depends simply on who is sharing secrets: if only one side is, use a one-way NDA; if both are, use a mutual one.
Key takeaways
- One-way NDA: only one party discloses confidential information and only the other party is bound to protect it.
- Mutual NDA: both parties disclose and both are bound — common in partnerships, joint ventures and M&A.
- The choice is driven by the direction of information flow, not by which party is “bigger.”
- A good NDA defines confidential information, permitted use, duration, and what happens on breach.
- For London’s deal-heavy, fast-moving business environment, having clear NDAs ready saves time and protects value.
What is an NDA?
A non-disclosure agreement (NDA), also called a confidentiality agreement, is a contract that stops a party from disclosing or misusing confidential information they receive. Businesses use NDAs before sharing sensitive material — financial data, customer lists, product plans, source code, pricing or trade secrets — with someone outside the business, such as a potential investor, supplier, partner or employee.
The purpose is straightforward: to allow a frank conversation to happen safely. Without an NDA, sharing your plans with a potential partner means trusting them entirely; with one, you have a contractual right to act if they misuse what you tell them. NDAs are among the most common business contracts precisely because almost every significant commercial conversation — a possible sale, a funding round, a new supplier relationship — involves disclosing something you would rather competitors did not know. They sit alongside other protections such as copyright and registered rights in a business’s wider IP strategy.
One-way (unilateral) NDA
A one-way NDA is used when only one party will disclose confidential information. Only the receiving party takes on confidentiality obligations; the disclosing party has nothing to protect because it is not receiving anything sensitive.
Typical scenarios:
- A company pitching its product or technology to a potential customer or investor.
- A business sharing confidential plans, designs or data with a contractor or consultant.
- An employer sharing sensitive information with a new employee.
Because the obligations run one way, these agreements are simpler and quicker to negotiate — there is no need to balance the interests of two disclosing parties, so they are often signed with little amendment.
Mutual (bilateral) NDA
A mutual NDA is used when both parties will exchange confidential information, so both are bound to protect what they receive. Each party is simultaneously a discloser and a recipient.
Typical scenarios:
- Two companies exploring a joint venture or partnership, where each must reveal how it operates.
- Merger or acquisition discussions, where each side opens its books to the other.
- Collaborations where both parties contribute proprietary technology, data or know-how.
Mutual NDAs are often perceived as fairer and more balanced, which can make negotiations smoother when both sides have something to protect — neither party feels it is taking on an obligation the other has escaped.
One-way vs mutual: at a glance
| One-way (unilateral) | Mutual (bilateral) | |
|---|---|---|
| Who discloses | One party | Both parties |
| Who is bound | The receiving party only | Both parties |
| Best for | Pitches, hiring, one-directional sharing | Partnerships, JVs, M&A |
| Complexity | Simpler | Slightly more involved |
| Perceived fairness | Can feel one-sided | Generally balanced |
What every NDA should include
Regardless of type, a robust NDA should clearly address:
- Definition of confidential information — what is covered, and what is excluded (for example, information already public, or already known to the recipient).
- Permitted purpose — the specific reason the information may be used, so it cannot be used for anything else.
- Obligations — non-disclosure, non-use, and limits on sharing within the receiving organisation (often only on a “need to know” basis).
- Duration — how long confidentiality lasts (often 2–5 years, sometimes indefinitely for genuine trade secrets).
- Return or destruction of information when the relationship ends.
- Remedies — what happens on breach, including the right to seek an injunction to stop further disclosure.
- Governing law and jurisdiction — which country’s law applies and where disputes are resolved.
A poorly drafted NDA — vague on what is confidential, or silent on duration — can be hard to enforce, giving false comfort. An NDA that looks reassuring but would not stand up if tested is arguably worse than none, because it encourages disclosure that the document cannot actually protect.
Common mistakes
- Using a one-way NDA when both sides are actually disclosing, leaving your own secrets unprotected.
- Over-broad definitions of confidential information that a court may decline to enforce because they are unreasonable.
- No time limit, or an unrealistically long one that makes the obligation hard to take seriously.
- Signing a counterparty’s template without reading the permitted-use, duration and jurisdiction clauses, which is where the real obligations sit.
- Treating the NDA as a formality and failing to actually manage the information once it is shared.
Do NDAs actually work?
An NDA is a contract, and like any contract its value lies partly in deterrence and partly in the remedies it provides. A well-drafted NDA makes the obligations explicit, which discourages casual misuse and gives you a clear basis to act if information is leaked. That said, enforcing an NDA can be challenging in practice — proving who leaked what, and quantifying the harm, is not always straightforward. This is why NDAs work best as one layer of protection alongside practical measures: only sharing what is necessary, sharing in stages as trust builds, marking documents as confidential, and keeping records of what was disclosed and when. The contract and the practical discipline reinforce each other.
NDAs with employees: a special note
NDAs and confidentiality clauses with employees deserve particular care, because the law treats them differently from commercial NDAs. Employers can legitimately protect genuine confidential information and trade secrets, and most employment contracts include confidentiality provisions for exactly that reason. However, a confidentiality clause cannot lawfully be used to prevent an employee from making a protected disclosure — that is, “whistleblowing” about wrongdoing — or from reporting a crime or cooperating with a regulator. Clauses that attempt to gag employees from raising legitimate concerns are unenforceable and can cause serious reputational damage to a business.
The practical lesson is that employee confidentiality terms should be proportionate and properly drafted: protecting real business secrets, while making clear they do not stop an employee exercising their legal rights. Overreaching clauses are not only ineffective; they can attract criticism and, in some contexts, regulatory scrutiny. If your business relies heavily on confidentiality from staff — for example in research, technology or client-sensitive sectors — it is worth ensuring those clauses are well-judged rather than copied from a generic template, so they protect what matters without crossing legal lines.
Why this matters for London businesses
London is one of the world’s busiest deal environments — investment pitches, partnerships, acquisitions and supplier negotiations happen at high volume and high speed. That makes two things valuable: having standard one-way and mutual NDA templates ready to go, and knowing which to reach for in a given conversation, so a deal is not delayed while paperwork is drafted from scratch. London businesses also frequently deal across borders, so it is worth checking governing-law and jurisdiction clauses rather than assuming English law applies — a counterparty’s template may specify a foreign jurisdiction that would make enforcement difficult and expensive. A few minutes spent choosing the right NDA and checking these clauses protects information that may be worth far more than the deal in front of you.
How Hayhills can help
Hayhills helps London and UK businesses protect confidential information and commercial IP through our Brand Protection and Intellectual Property service. We advise on whether a one-way or mutual NDA fits your situation, review NDAs put in front of you, and help you put clear, enforceable confidentiality terms in place before you share anything sensitive.
What is the difference between a one-way and a mutual NDA?
A one-way NDA protects information disclosed by one party only; a mutual NDA protects information disclosed by both parties, binding each of them.
When should I use a one-way NDA?
When only one party is sharing confidential information — for example, pitching to an investor or sharing plans with a contractor.
When should I use a mutual NDA?
When both parties will share confidential information, such as in a joint venture, partnership or merger discussion.
Is a mutual NDA fairer?
It is often seen as more balanced because both parties take on the same obligations, which can ease negotiations.
How long should an NDA last?
Commonly two to five years, though trade secrets may be protected indefinitely. The right period depends on how long the information stays sensitive.
Are NDAs enforceable?
Yes, a well-drafted NDA is an enforceable contract, but enforcement can be difficult in practice, so it works best alongside practical confidentiality measures.
This article is for general information only and does not constitute legal advice. Hayhills Limited, trading as Hayhills Legal Advisory, provides non-reserved legal advisory services. Always check current requirements at GOV.UK.