The concern of Commons home affairs committee chair Keith Vaz MP that Mayor Johnson " may have misled " him and his colleagues over the success of a young offenders rehabilitation scheme supported by the Mayor in the Heron wing of HMYOI Feltham will not have been soothed by exchanges at a London Assembly meeting last week. The panel , which scrutinises the progress of Boris's Time for Action policies for young people, heard City Hall officers confirm that his claim to the committee that, "We cut re-offending rates in that wing from 80% to 19%" should have been laden with caveats and that the Mayor's office had been made aware of this. The re-offending rate wrangle began when Sir Michael Scholar, chair of the nation's independent statistics watchdog, wrote to Vaz saying that Boris's figures "do not appear to stand up to scrutiny." He said, among other things, that the 19% re-offending rate claim came from "internal management information" bearing the caveat that it did not "represent a re-conviction rate and should not be used publicly." And yet it was. Vaz wrote to Boris seeking clarity. Boris replied, saying that "interim figures" calculated by the London Criminal Justice Partnership for the Heron wing unit's first year of operation "suggest" that the re-offending rate for the unit's first year of operation was 19%. Just a hint of a belated caveat or two there, though the letter did not even address the point about the figure not being for use in public. Had Boris, perhaps, made an innocent mistake when in the presence of Vaz and company? Panel chair Joanne McCartney asked Christian Steenberg, the Time for Action programme manager, if Boris was made aware of the caveats that applied to the 19% figure and that it wasn't to be quoted publicly. "They have been made aware, but this has been a concern throughout, so yes they have been made aware," Steenberg replied. I think his use of "they" must have referred to the mayor's office collectively. McCartney tried to pin this down: "And the mayor has been made aware?" At this point Jeff Jacobs, the GLA's head of paid service and the "sponsoring director" of Time for Action broke in. "Well, Kit has been made aware." Kit, of course, is Kit Malthouse, Boris's trusted deputy for policing. Jacobs reminded the panel that Malthouse had mentioned the 19% figure in March when he'd updated it about progress at the Heron wing unit, and had relayed all the caveats in the process. There are other aspects to this tasty number crunch, including whether Boris's "around 80%" re-offending rate benchmark was the appropriate one. Even leaving those aside we have a situation where Boris has claimed that the Heron unit is enjoying remarkable success when in fact that this may not be case, despite his own policing deputy previously qualifying the stat and despite his own staff appearing to think that he should have been aware both of the 19% figure's fragility and its unsuitability for public consumption. Boris's over-claiming about the Heron wing unit has not only happened in front of a Commons committee in recent months but in the pages of the Sun and the Telegraph too. Moreover, Steenberg confirmed that the latest - no doubt caveated - indications from the unit are that the re-conviction rate of former Heron Wing unit inmates is almost 40% and that no truly reliable appraisal can made until early next year. Keith Vaz has yet to reply to Boris's clarifying letter. When he does, it could be a interesting read. Boris Johnson London politics Youth justice London Dave Hill guardian.co.uk © 2011 Guardian News and Media Limited or its affiliated companies. All rights reserved. | Use of this content is subject to our Terms & Conditions | More Feeds