Forgery is more than copying a signature. In England and Wales it is a serious criminal offence under the Forgery and Counterfeiting Act 1981, carrying a maximum of ten years' imprisonment. This guide explains, in plain English, what counts as forgery, what a "false instrument" is, and the related offences you should know about.
What is forgery?
Under section 1 of the Forgery and Counterfeiting Act 1981, a person is guilty of forgery if they make a false instrument, intending that it be used to induce somebody to accept it as genuine and, by reason of accepting it, to do or not do some act to their own or another's prejudice.
Breaking that down, the prosecution must generally show:
- a false instrument was made;
- the maker intended it to be accepted as genuine; and
- the intention was that someone would act (or refrain from acting) to their prejudice as a result.
What is an "instrument"?
An "instrument" is widely defined and is not limited to formal legal documents. It includes any document, whether formal or informal, and certain other things such as discs, tapes or other devices on which information is recorded or stored. So forged contracts, cheques, certificates, identity documents, references and electronic records can all be instruments.
When is an instrument "false"?
An instrument is "false" in a number of situations set out in the Act, broadly, where it tells a lie about itself: for example, where it purports to have been made or altered by someone who did not make or authorise it, or on a date or in terms that are not genuine. The key idea is that the document misrepresents its own authenticity or authority, not merely that its contents are untrue.
The related offences
The Act creates several connected offences, including:
- Using a false instrument (section 3), using an instrument you know or believe to be false, with the same kind of intent. You can commit this even if you did not make the forgery.
- Copying a false instrument, and using a copy of a false instrument.
- Offences relating to certain specified instruments (such as money orders, stamps and certain official documents), and the separate counterfeiting of currency.
- Possession of certain false instruments or materials.
Penalties
Forgery and the main related offences are serious. On conviction on indictment, the maximum penalty is ten years' imprisonment, reflecting how seriously the law treats documents that undermine trust in commerce and officialdom. The actual sentence depends on the circumstances, the harm intended or caused, and the offender's role.
Why it matters in business
Everyday business documents (invoices, references, signatures, certificates and electronic records) can all be instruments. Altering or fabricating them, or using ones you know to be false, can cross into criminal territory, quite apart from any civil liability. If you suspect a document is forged, take advice rather than acting on it.
Key takeaways
- Forgery is making a false instrument intending it to be accepted as genuine and acted on to someone's prejudice (Forgery and Counterfeiting Act 1981, s 1).
- An "instrument" is broad, documents and certain recorded data; "false" means it lies about its own authenticity or authority.
- Related offences include using a false instrument (s 3), copying, and possession.
- The maximum penalty is ten years' imprisonment.
Sources
- Forgery and Counterfeiting Act 1981, sections 1, 3 and related provisions (making/using false instruments; penalties)
- Statutory definitions of "instrument" and "false" under the 1981 Act
--- This article is general information about the law of England & Wales as at 2026, not legal advice. For advice on your circumstances, consult a qualified solicitor.