The Tories faced fresh questions on Wednesday over their use of crime statistics after the House of Commons library released a note that raised doubts about their claims that violent crime has risen 44 per cent under Labour.

Chris Grayling, shadow home secretary, had asked the library’s statistician to examine the impact of a 2002 change in police recorded crime figures so he could challenge Labour claims that violent crime has fallen during its time in office.

His adjustment was used to support Mr Grayling’s claims that violence had in fact risen.

However, the statistician’s note states “police recorded crime is not viewed as a reliable indicator of trends” and should be viewed only alongside the British Crime Survey. Statisticians say the BCS is a better guide to trends, but the Tories claim it underestimates violent offences.

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