SERIOUS offenders are escaping with police cautions because forces are chasing performance targets, it was claimed yesterday.

The rising use of on-the-spot fines and cautions was blamed on pressure to improve crime detection rates.

The news came as figures disclosed a big rise in cautions for tens of thousands of violent and sexual offences. Figures obtained by David Ruffley , the shadow police minister, showed that from 2002 to 2006, there was a 142 per cent rise in the use of cautions for violence against the person from 23,607 to 57,273. There was a 75 per cent increase in cautions for robbery and a 60 per cent rise for sexual offences.

Digby Johnson, of the Johnson Partnership in Nottingham, said: "Offenders who would normally face court and serious sentences are walking away with a ticket in their back pocket.''

The Police Federation of England and Wales blamed the pressure on forces to improve crime detection rates. But the Ministry of Justice said: "Fixed-penalty notices and cautions enable police to deal swiftly with low-level offending, freeing them up to spend more time on front-line duties and more time investigating violent, dangerous or sexual offences.''