Under the Police and Criminal Evidence Act (PACE) 1984 as amended, the police may take, without consent, DNA (and fingerprints) from persons who have been arrested for, charged with, informed they will be reported for or convicted of a recordable offence.
These may only be used for the purposes of prevention and detection of crime, the investigation of an offence, the conduct of a prosecution or, since April 2005, for the purposes of identifying a deceased person.
Procedures on the taking of such samples and guidance to officers are given in PACE Codes of Practice, Code D. These state that the person should be informed of the reason for taking the sample, if appropriate the grounds on which the relevant authority to take the sample has been given, and that information derived from the sample may be subject to a speculative search on the National DNA Database.