61% of rejected claims for the Personal Independence Payment (PIP) are overturned on appeal - inflicting unnecessary stress and extra expense on people, say campaigners.
Paralympian Tanni Grey-Thompson, a campaigner for disabled people and DR UK ambassador, said the rate of successful appeals exposed a system that "isn't working".
Lady Grey-Thompson said:
"There must be so much money wasted - I want the Government to look at this urgently. It is very stressful to go to an appeal. It can take a lot of time and you may not have very much money while it is going on."
Liz Sayce, CEO Disability Rights UK, said:
"Appeals can take a year to be heard - that's a year that people might have to make do with a significant drop of income when they have the additional costs of disability.
'Many disabled people simply give up. They can't face the stress and grief of going through a further process to try and get benefit, even when they're entitled to it."