Caution
The formal warning given by police on arrest or before questioning: 'You do not have to say anything. But it may harm your defence if you do not mention when questioned something which you later rely on in court. Anything you do say may be given in evidence.'
Independent editorial summary — not the official statute text. Read the official version on legislation.gov.uk.
Official interviewing guidance confirms the wording and when it must be used: the suspect must be cautioned 'immediately before you question' them, in the terms: 'You do not have to say anything. But it may harm your defence if you do not mention when questioned something, which you later rely on in court.' followed by 'Anything you do say may be given in evidence'.
If the suspect does not understand, or the interviewer doubts that they do, the guidance requires a simplified version to be given and understanding checked again: 'I am going to ask you some questions. You do not have to answer any of them unless you want to.' The wording also differs slightly outside England and Wales — in Northern Ireland the standard caution is phrased differently, showing the caution's exact words are not fixed across the whole of the UK.
Related terms
Official sources
This explanation is drawn from the official sources below; every substantive statement is verified against them. For advice on a specific matter, see our find help page.