Coalition's welfare strategy 'failing', documents reveal
19 June 2014 Last updated at 19:28 BST
The new disability benefit is helping fewer people get jobs, while its rising cost is a big financial risk for the UK, an internal government memo says.
The memo, obtained by the BBC, says the Department for Work and Pensions is struggling to deliver employment support allowance (ESA).
ESA was introduced in 2008 to replace incapacity benefit.
The government acknowledged there had been problems but said it was bringing in a new firm to do tests for ESA.
The document also says claimants face an average nine-month wait after assessments. The target is three months.
Michael Buchanan reports.