Why Boris Johnson needs to provide London with trustworthy statistics
London Mayor Boris yesterday caused a stir by calling the head of the UK Statistics Authority a "Labour Stooge".
As we said at the time, this slur was both misplaced and unfair, and people who care about public trust in official statistics would be disappointed to see one of its champions slighted by a high-profile politician.
However there is an important point underpinning this spat.
Mr Johnson's outburst was prompted by a question from Assembly Member Joanne McCartney, who had asked the Mayor: "Will you now sign up to the Code of Practice for Official Statistics as all Government departments do?"
This is something Full Fact has also called for the Mayor to do, after we found serious problems with his use of transport crime and reoffending figures.
As a timely reminder of the scale of the problem, London blogger Adam Bienkov today points out that the Mr Johnson's claims on his crime record are not all they seem.
The BackBoris website claims that since the Mayor took office in 2008, he'd cut crime by 9.4 per cent and robberies by 18.5 per cent.
However looking at the Metropolitan Police crime data, neither claim is supported by the figures.
In the 2007/08 financial year, the last period of Ken Livingstone's time in City Hall, there were 862,032 crimes recorded across London by the Met. For the 2010/11 financial year, the figure was 823,339. This is a drop of 4.5 per cent, much lower than the Mayor's claim.
Similarly, the fall in robberies is more modest. In 2007/08 37,000 robberies were recorded by police, which by 2010/11 had fallen by 3.2 per cent to 35,833. If this is compared to the 12 months of data to October 2011, there has actually been a slight rise, perhaps accounted for by the summer's riots.
The explanation given to Mr Bienkov for this discrepancy was that the Mayor was comparing his record over the past three years with that of his predecessor between 2005 and 2008.
Full Fact will of course be paying close attention to the claims of all prospective Mayors as campaigning heats up ahead of next spring's election.
When Britain went to the polls in May we found that the channels available for correcting the record often failed to keep pace with the brisk pace set on the campaign trail.
One newspaper inaccuracy about the Alternative Vote was only corrected in June, nearly two months after the referendum on changing voting systems. Clearly this is too late to prevent the electorate from being misinformed when they enter the voting booth.
At election time therefore it is even more important than usual that the claims placed in the public domain are accurate and open to public scrutiny.
By agreeing to sign up to the Code of Practice for Official Statistics, Boris Johnson could make a real statement of his commitment to an informed and enlightening debate ahead of next May's election.
Despite his dismissive tone, Mr Johnson did promise to consider the suggestion yesterday. We hope he will quickly realise the real benefits this would bring to Londoners.