Benefit claimants face "long and uncertain delays" as a consequence of the slow processing of claims under the Government's new Personal Independence Payment, the National Audit Office said.
The head of the NAO Amyas Morse claimed the Department of Work and Pensions did not allow enough time to see if the assessment process could handle a large number of claims.
Mr Morse added:
The Department did not allow enough time to test whether the assessment process could handle large numbers of claims.
As a result of this poor early operational performance, claimants face long and uncertain delays and the Department has had to delay the wider roll-out of the programme.
Because it may take some time to resolve the delays, the Department has increased the risk that the programme will not deliver value for money in the longer term.
More top news
The Trump administration is greatly expanding the number of illegal immigrants in the country who are considered a priority for deportation.
The feature on the Facebook-owned app is strikingly similar to similar "story" elements on Instagram and Snapchat.
Merseyside Police are hunting convicted murderer Shaun Walmsley after two armed men helped him escape custody while on a hospital visit.