A computer programme that calculates whether a burglary is worth investigating, is "insulting" to victims and risks alienating the public, the head of the Police Federation has warned.

Norfolk Constabulary has been trialling a new system which uses sophisticated algorithms to determine whether there is any point attending a break in.

Officers input various details about the offence, such as whether there are clues including fingerprints or CCTV, and then the computer will suggest whether it is worth devoting any police time to.

The system is intended to help police chiefs work out how best to deploy resources as forces everywhere struggle to cope with reduced budgets and increasing demands.

But John Apter, the recently elected chairman of the Police Federation, which represents rank and file officers, warned the introduction of such systems represented a slippery slope which threatened to erode the trust that exists between the public and the police.