More than 150,000 people deemed fit to work by French IT company Atos have won appeals in a process costing taxpayers more than £30million a year, it found.
And some had their benefits stopped for “failure to attend” a test when they had not even been booked in.
The Commons work and pensions select committee condemned the blunders.
Tory MP Simon Hart said people were deemed totally fit to work in one test, only to be found in the appeal they were unfit to get a job.
Committee chairman Dame Anne Begg said some of the blame needed to fall on the Government for designing “flawed” assessments which Atos had to work with.
She said “considerable efforts” had been made to improve things, but more needed to be done