The government has been criticised by MPs over the "disastrous" role of the private firm Atos in carrying out fit-to-work assessments.
Atos holds the contract to oversee assessments that are part of a move to increase the number of people taken off benefits and moved into employment.
It was paid more that £112m in the last financial year and carried out around 738,000 face-to-face medical tests on benefit claimants.
However speaking during a Westminster Hall debate on 4 September 2012, the chair of the Work and Pensions Committee, Dame Anne Begg, said that the government "failed to grasp" problems in the system.
Nearly four out of 10 appeals against benefit decisions by Atos have been successful, and Dame Anne said it was "not enough for the government to say that genuine claimants have nothing to fear".
Atos is one of the official sponsors of the London Paralympic Games, leading to protests by some disability rights campaigners against the company's involvement.
The chair of the Westminster Hall debate, Phillip Hollobone, threatened to suspend the sitting at one point, as members of the public gallery heckled the outgoing Work and Pensions Minister, Chris Grayling.
The minister - speaking on the day of his promotion to Justice Secretary - denied that medical assessments were "a financial exercise".
He refused to undertake a "major overhaul" of the system, claiming there was a lack of evidence that changes were needed.