Thousands of disabled people who have been assessed under new government rules as fit for work are having the decision overturned on appeal.
BBC Inside Out East has found that of the 146,200 appeals that have been heard to date, 56,500 (more than a third), have been upheld in favour of the claimant.
Atos, the company carrying out the tests, called the Work Capability Assessment (WCA), is being paid £100m a year by the UK government.
Peter Reynolds from Linton in Cambridgeshire is one of thousands who believe they were wrongly assessed.
Two years ago he fell off a fork lift truck and is chronically ill.
He has problems with his lungs and his lymphatic system has stopped working.
He uses a wheelchair, needs constant care and has to wear a body suit all the time. He is in and out of hospital on a regular basis.
After his accident Mr Reynolds received sickness benefit but within weeks under new government rules he was asked to prove the extent of his illness.
He was assessed by Atos as being a suitable case to return to work.
He then went to the Citizens Advice Bureau (CAB) who organised a reassessment and he was evaluated as not fit for work.
His doctor has told him he will never work again.
Pebble Padfield, the CAB adviser in Cambridge who assisted Mr Reynolds, believes that the assessment process is flawed.
"I think it is undeniable that the onus of proof is on the claimant to show that they are not fit for work.
"How can somebody with chronic depression or with back pain have the confidence and the articulacy at that moment to prove their condition to that person," she said.
For someone like Mr Reynolds the tragedy is he would love to work if he could but his life is taken up with managing his illness.
"If I hadn't got all that is wrong with me I would bite anybody's hand off to give me a job.
"I would sooner be out in the work place doing a decent day's work than being in the mess I am in."
Inside Out asked Atos to comment on the high number of incorrect assessments.
The company said it focused on quality and satisfaction but it was "recognised by all parties" that the number of appeals "is higher than would be liked" but the total number of appeals was just 7% of all the assessments it carried out.
The BBC asked the Department for Work and Pensions if it was satisfied with the way Atos was carrying out its contract.
It told BBC Inside Out the department would "continue to review and refine the WCA to ensure that it is more effective, fairer for all claimants and as a result fairer for the taxpayer".
A new review of the benefit assessment is being undertaken by the government and should be published by the end of the month.
The full story can be seen in Inside Out in the East on Monday at 19:30 GMT.