An NDA creates a legally binding obligation of confidentiality. In the UK, they are governed by contract law and trade secrets legislation, but have important limits.

• NDAs cannot prevent reporting of criminal activity to police or regulators
• Cannot be used to silence harassment or discrimination victims (post-2019 reforms)
• Trade secrets protected under Trade Secrets (Enforcement) Regulations 2018
• Indefinite NDAs are harder to enforce — courts prefer reasonable time limits
• Must clearly define what constitutes "confidential information"
• Courts will not enforce clauses that are grossly one-sided or unconscionable
• Breach can result in injunctions, account of profits, and damages
• PILON / garden leave clauses in employment NDAs have specific rules

Legal reference: Trade Secrets (Enforcement, etc.) Regulations 2018; Public Interest Disclosure Act 1998; Equality Act 2010