The shadow home secretary has been criticised by the statistics watchdog for his use of crime figures.

Sir Michael Scholar, chairman of the UK Statistics Authority, has written to Conservative frontbencher Chris Grayling because the MP's presentation of violent crime statistics seems "likely to damage public trust in official statistics", the letter stated.

On Wednesday Grayling quoted police recorded crime statistics to argue that violent crimes against the person have increased under Labour.

However, the UK Statistics Authority have pointed out that these police figures were affected by the introduction of the National Crime Recording Standard in 2002-03 because a some crimes have been redefined as violence against the person.

Scholar's letter to Grayling pointed out that the British Crime Survey would have been a better source for comparing crime rates in the late 1990s and now because its methodology has remained unchanged since it was established in 1981.

The BCS, although it does not show local crime rates, shows that there has been no increase in respondents experiencing of violent crime since the late 1990s.

Scholar also criticised the Tories for ignoring "high profile comments" on statistics publications pointing out that the police figures were not comparable over time because of the changes to recording methods.

A note from the authority says it "appreciates that political debate involves the selection and interpretation of statistics and other evidence to support an argument", and Scholar told Grayling that he did "not wish to become involved in political controversy".

However, the authority's note says: "Where we see that official statistics have been presented or quoted in a way that seems likely to mislead the public, we will publicly draw this to the attention of those involved."

Grayling has defended his use of the data, arguing that the Home Office has drawn comparisons from the same figures. "We don't create crime figures," he said. "We use the official crime figures published by the Home Office."

But home secretary Alan Johnson accused the party of trying to "to talk Britain down" with the "dodgy statistics".