Revision of Have murders in London increased in the last year? from 10 April, 2012 - 15:19
"When I was elected Mayor we had a peak of I think over 200 murders a year ... By the time I had left ... muders were down to 160 - But in the last year there's been an 8 per cent increase in murders"
Ken Livingstone, BBC News London, 26 March 2012
"Ken Livingstone’s previous false claims on crime: ... Ken Livingstone claim: In the last year there has been an 8 per cent increase in murders"
BackBoris 2012.com, 4 April 2012
"Comparing my term against that of my predecessor: Murders have decreased by 25.9%, with the lowest rate since 1978"
Boris Johnson, 2 April 2012
Mayor of London Boris Johnson and Labour challenger Ken Livingstone both stepped up their campaigns last week, with both candidates publishing their crime manifestos.
Amidst the debate on crime, one bone of contention between the candidates has been the London's murder rate. Boris Johnson claims that murders have fallen by a quarter since he entered office in 2008.
Meanwhile, Ken Livinstone has come under attack for claiming that murders had increased by eight per cent in the last year - with both the 'BackBoris' campaign website and 'NotKenAgain' site calling the claim "false" and "unfounded".
So what do the figures actually show?
Analysis
Seeing the Boris campaign's point of view is not difficult when looking at the Metropolitan Police's own crime statistics. These are updated monthly, and at time of writing the most recent data is for February 2012.
The latest available statistics for 'homicide' show clearly that, from March 2010 to February 2011 there were 137 recorded homicide offences in London. From March 2011 to February 2012, this had fallen to 104.
So the most recent data tells us that murders have decreased by 24 per cent in the last year. They have decreased by an almost identical amount when comparing the financial years rather than the previous 12 months.
So where does Ken's eight per cent decrease come from?
Ken's campaign team explained to Full Fact that the figure used by their man during the BBC interview came from the now defunct Metropolitan Police Authoirty (MPA) that formerly published crime statistics.
Looking at the last published set of MPS crime statistics for October last year, they show that, from November 2010 to October 2011, homicides had increased by nine offences on the previous year. In other words, homicides had increased by 7.6 per cent.
So while Ken's claim is founded on published figures, those figures are now out of date. At the time he made his claim, the figures for January or February 2012 would have been available.
The bigger picture
To assess the wider picture, figures can be drawn from historical data tables from the Metropolitan Police recorded crime. These tell us the number of homicide offences in each financial year since 2000.
Figures are also available for 'Undetected Homicides' since 2000. These refer either to homicides currently under investigation, those under review before investigation, cases that have been dropped or defeated in court, those where the main suspect has died, or those where the defendant has been released on appeal.
