Victims of petty crime like car theft in Britain are being increasingly told to turn 'detectives' and investigate their own cases by some police forces.

The Inspectorate of Constabulary, the official police watchdog for England and Wales, found in a report that this "do-it-yourself" or DIY, trend was linked with some high-volume types of offences, such as car crimes, criminal damage and non-residential burglaries and warn that these offences are on the verge of being decriminalised.

"Her Majesty's Inspectorate of Constabulary finds this expectation by these forces that the victims should investigate their own crimes both surprising and a matter of material concern," says the report.

"The police have been given powers and resources to investigate crime by the public, and there should be no expectation on the part of the police that an inversion of that responsibility is acceptable," it adds.