This morning’s Today programme provided another of those ‘mustn’t miss’ moments, as presenter Evan Davis  took the Conservatives’ Shadow Home Secretary Chris Grayling to task over the party’s misleading use of crime statistics.

Last week Mark Easton, the BBC’s Home Affairs editor, had asked ‘Are the Tories being honest with their claims on violent crime’:

Last week, David Cameron told me that one reason he could justify the phrase “broken society” was because of “significant” increases in violent crime, notably gun and knife crime in Britain.  When I challenged him to produce the evidence, his party press office sent the BBC a list of statistics. It emerges that the only way the Conservative leader can back up his claims is to ignore the klaxon warning attached to the statistics following changes in the way police record violent incidents in England and Wales.

Tory Central Office e-mailed this claim to me: ‘Violent crime has increased from 615,985 offences in 1998-9 to 1,034,972 in 2008-9, an increase of 68 per cent’. The document cited, however, includes this massive caveat: ‘The National Crime Recording standard was introduced in April 2002. Figures before and after that date are not directly comparable’. And yet, that is exactly what Mr Cameron appears to do.

The Conservatives sent an email to all their MPs and candidates, with the data broken down into police authority and crime and disorder partnership areas. Local Tories have not been slow to act on this data. In Milton Keynes, local Conservative MP Mark Lancaster issues a statement last week claiming that there were 6,015 “violent attacks” in the town last year, a 236% increase over the past decade.

The Milton Keynes Citizen carried an angry rebuttal from the town’s police commander Nikki Ross, criticising the MPs statement as ‘extremely misleading’. She told the paper that the figure quoted by Lancaster included ‘everything from public order offences, to harassment, to allowing a dog to be out of control in a public place’, stating, ‘the actual number of people who were victims of serious violence was 81’ . The problem is that the phrase ‘violent attacks’ does not equate directly with the crime category ‘violence against the person’. For instance, if someone swears at you and you report it to the police, the incident is recorded as a crime of ‘violence against the person’.

Chris Grayling strongly denied claims that the Conservative Party had been using crime statistics in a highly misleading way. However Evan Davis was in a particularly tenacious mood. Over and over again he challenged Grayling as to whether the shadow cabinet member knew that the recording method had changed and the data should not have been compared?

Rattled, Grayling accused Davis of being pedantic, denying the figures were ‘apples and oranges’. But Davis was ready with the killer blow:

“Those people who listened to you and thought the current government was selective or mendacious in its use of statistics and who had hoped that you would somehow be different should now acknowledge that your benchmark for your use of statistics is what the government does. So if they use dodgy statistics you will too? You are aspiring to be absolutely no better, cleaner, clearer, more honest than they are?”

Grayling tried to refute Davis’s points, but found himself hemmed in at every turn.  So he turned his fire onto discrediting the widely-respected British Crime Survey. Grayling’s point seemed to be that you couldn’t trust a professionally compiled survey and that more accurate results could be found by talking to ‘anyone on the streets’. In fact the BCS shows that violent crime is now lower than at any time under the Thatcher or Major governments – peaking in 1995 -and that it has been falling pretty consistently ever since to around half of its previous levels. It’s interesting to note that Chris Grayling is so ill-informed about the BCS that he wrongly announced the survey doesn’t record crime committed by those aged under 16. It does. Until last year, it did not record crime committed against the under 16s, but now has a lower age limit of 10.

You can hear the full interview on the BBC’s web site, starting 1 minute 30 into the programme.