"A person whom there are grounds to suspect of an offence must be cautioned before any questions about it (or further questions if it is his answers to previous questions which provide the ground for suspicion) are put to him regarding his involvement or suspected involvement in that offence if his answers or his silence(i.e. failure or refusal to answer a question or answer satisfactorily) may be given in evidence to a court in a prosecution. He therefore need not be cautioned if questions are put for other purposes, for example, solely to establish his identity or his ownership of any vehicle or to obtain information in accordance with any relevant statutory requirements (see paragraph 10.5C) or in furtherance of the proper and effective conduct of research, (for example to determine the need to search in the exercise of powers of stop and search or to seek co-operation when carrying out a search) or to seek verification of a written record in accordance with paragraph 11.13."