Conservative chairman Grant Shapps has been rebuked by the UK's statistics watchdog for wrongly claiming that nearly one million people on incapacity benefit (IB) had dropped their claims rather than face medical checks.
In fact, official figures showed that just 19,700 IB recipients withdrew their claims before facing work capability assessments as part of the transfer to the new employment and support allowance (ESA) between March 2011 and May 2012, said UK Statistics Authority chairman Andrew Dilnot.
Mr Dilnot said that the Tory chairman appeared to have "conflated" figures for IB claimants being moved onto the new benefit with those for new applicants for ESA who had not previously been in receipt of incapacity benefit.
Some 878,300 of these claims were closed before undergoing assessment over a three-and-a-half year period from October 2008 to May 2012.
Shadow work and pensions secretary Liam Byrne called on Mr Shapps to apologise for "trying to pull the wool over people's eyes" in the latest of a series of cases in which Conservative ministers have been rapped over the knuckles for misusing statistics.
Earlier this month Work and Pensions Secretary Iain Duncan Smith was rebuked for claiming that figures showed the Government's benefits cap had driven 8,000 people to return to work.
In February, Mr Dilnot said David Cameron was wrong to claim in a party political broadcast that state debt was falling. And in December last year, he asked Health Secretary Jeremy Hunt to stop claiming that he had increased the NHS budget in real terms in each of the last two years.
Mr Dilnot's latest comments came in a letter to Labour MP Sheila Gilmore, who raised a complaint over a Conservative press release issued in March this year under the headline: "Nearly 1 million people drop incapacity benefit claim before medical test."
Ms Gilmore also complained that press reports of the issue implied that those dropping claims were doing so because they had never really been ill.
In his letter, Mr Dilnot pointed to research by the Department for Work and Pensions (DWP), which found that "an important reason" why claims were withdrawn before assessments were completed was that "the person recovered and either returned to work or claimed a benefit more appropriate to their situation".
In the press release, Mr Shapps said: "Our reforms are about freeing people from a system of dependency that's trapped them and their families for decades - and people are getting back into work as a result. These figures demonstrate how the welfare system was broken under Labour and why our reforms are so important."
But Mr Dilnot found: "Having reviewed the article and the relevant figures, we have concluded that these statements appear to conflate official statistics relating to new claimants of the ESA with official statistics on recipients of the incapacity benefit (IB) who are being migrated across to the ESA.
"According to official statistics published by the Department for Work and Pensions (DWP) in January 2013, a total of 603,600 recipients of IB were referred for reassessment as part of the migration across to ESA between March 2011 and May 2012. Of these, 19,700 claims were closed prior to a work capability assessment in the period to May 2012.
"The figure of 'nearly 900,000' referenced in the article appears to refer to the cumulative total of 878,300 new claims for the ESA (i.e. not pre-existing IB recipients) which were closed before undergoing assessment in the period from October 2008 to May 2012."
Mr Byrne said: "This is a Government that doesn't like to let the facts get in the way of a good story.
"Grant Shapps may know a thing or two about making things up but it really is outrageous that the Tories have been caught yet again misusing statistics for their own ends. People want a Government that deals with the problems facing Britain, with a plan for getting growth and jobs in our economy, not one that repeatedly misleads the public.
"Grant Shapps needs to come clean and apologise for trying to pull the wool over people's eyes."
A Conservative spokesman said: “As Andrew Dilnot has said in his letter, DWP research shows that 'an important reason why ESA claims in this sample were withdrawn or closed before they were fully assessed was because the person recovered and either returned to work, or claimed a benefit more appropriate to their situation.
“This Government is fixing the welfare system to make work pay. We're capping benefits so that no out-of-work household can claim more than the average working family earns and introducing Universal Credit so it always pays to work.
“The same old Labour Party have opposed every single measure we've taken to fix welfare.”