A subscribing witness is a person who is physically present when a party signs a legal document and then signs the document themselves to attest that they have witnessed the signature. The subscribing witness’s signature and details (for example, name, address and occupation) provide evidential support that the document was properly executed.In UK and Irish practice, subscribing witnesses are commonly used for deeds, wills, powers of attorney and certain company and land registration documents. Their role is primarily evidential: they may later be called to prove due execution or the authenticity of a signature, especially where validity is contested.Across England and Wales, Scotland, Northern Ireland and Ireland, the expression “subscribing witness” is widely understood in practice, although the precise statutory requirements for witnessing and attestation vary by jurisdiction and by instrument (for example, under succession, property, company and mental capacity legislation). Some statutes and procedural rules refer expressly to subscribing witnesses or attesting witnesses; in other contexts it is a descriptive term. Failure to use an eligible subscribing witness, or to comply with formalities, can render a document invalid or difficult to prove.