Iain Duncan Smith criticised over benefit cap figures
The statistics watchdog has criticised figures used by Work and Pensions Secretary Iain Duncan Smith to argue that his benefits cap was working.
He said that the cap was having "the desired impact" as 8,000 people who would have been affected had got jobs.
But the watchdog said that was not backed by the figures, which also did not comply with the code of practice.
A cap on the total benefits working age people can receive is being rolled out across England, Scotland and Wales.
The UK Statistics Authority was asked by unions to investigate comments made by Mr Duncan Smith in a Daily Mail interview, which coincided with the release of figures by his department on households which could be hit by the cap, and on Jobcentre Plus work with people who could be affected.
The figures state that although 8,000 people who would potentially have been hit by the cap had got jobs, they were "not intended to show the additional numbers entering work as a direct result of the contact".
And they point out that although the number of households expected to be affected had fallen by 16,000 from 56,000 to 40,000 - that was due to policy changes and changes due to the "normal benefit caseload change", and did not assume any "behavioural change" as a result of the cap.
But the article suggested that the 16,000 "decided to act" after Mr Duncan Smith's department wrote to them, telling them their benefits were to be cut.
And the secretary of state is quoted as saying: "The benefit cap sets a strong incentive for people to move into work and even before the cap comes in we are seeing thousands of people seeking help and moving off benefits ... Already we've seen 8,000 people who would have been affected by the cap move into jobs. This clearly demonstrates that the cap is having the desired impact."
Andrew Dilnot, the chairman of the UK Statistics Authority, has written to Mr Duncan Smith to say the two sets of figures released in April "do not comply fully with the principles of the Code of Practice [for official statistics]".
He said he had been assured, following an earlier statistics complaint against the department, that DWP staff had been told about their obligations to make sure statistics met official guidelines adding that the watchdog now sought "further assurance" on the matter.
And he told the TUC's Nicola Smith, who made the complaint that Mr Duncan Smith's quoted comments linking the 8,000 jobseekers to the benefits cap were "unsupported by the official statistics published by the department".
TUC General Secretary Frances O'Grady said: "Only people with weak arguments need to make up statistics. Of course we need a welfare system that guards against abuse, but this government is now causing real hardship and worry to many who have done nothing to cheat the system and are desperate to work."
And Shadow Work and Pensions Secretary Liam Byrne accused Mr Duncan Smith of "living in la la land".
"His ideas don't work so he's now literally making up stories," he said.
"For the third time in just six months, the head of the UK Statistics Authority has written to ministers to warn them about their misuse of statistics."
But a spokesman for the DWP said: "The secretary of state has long held the position that the benefit cap would have an impact on the behaviour of claimants.
"As the minister for employment made clear in a recent interview, DWP staff and claimants are telling us the cap is impacting behaviour and leading to those affected finally entering the world of work."