Millions of pounds are being wasted on reassessing people with Parkinson's for benefits even though their condition will never improve, campaigners have warned.
Analysis by Parkinson's UK suggests it will cost £3 million to reassess everyone with Parkinson's as they switch over from disability living allowance (DLA) to its replacement personal independence payment (PIP).
The charity says £1.3 million of this will be spent reassessing those who were already judged to have the highest level of need.
The Department for Work and Pensions said it did not recognise the figures and there are a higher proportion of people with Parkinson's on the highest rate of PIP than there are on DLA.
Phil Reynolds, senior policy and campaigns adviser at Parkinson's UK, said: "Under PIP, people with Parkinson's are being forced through a broken assessment process that fails to understand that they won't get better.
"We've even heard of people with Parkinson's being asked by assessors how long they expect to have Parkinson's for.
"PIP is designed to help people manage the significant extra costs of their condition and stay independent, but a quarter of people with Parkinson's have lost some or all of their award. As a result, people are having their cars taken away, losing their independence and seeing their health deteriorate. This is simply unacceptable."
With 12 months to go until PIP is fully rolled-out, the charity is calling on the Government to automatically move people with Parkinson's on the highest rate of DLA to PIP, without the need for reassessment.
The National Audit Office puts the admin cost of each new claim at £182.
As of May 2015, the final snapshot before DLA reassessments began, there were 16,845 DLA cases in payment to people with Parkinson's, of whom 7,657 received the highest rates of both parts of the benefit.
A Department for Work and Pensions spokeswoman said of the charity's statement: "We do not recognise these figures. The fact is over half of claimants with Parkinson's are now getting the highest level of support under PIP - much more than under DLA.
"PIP is a better benefit which takes a much wider look at the way an individual's health condition or disability impacts them on a daily basis, and is tailored to suit each individual's needs. Regular reassessments mean we can ensure people with degenerative conditions like Parkinson's get the help they need as their condition changes."
In 2016/17, 65% of the 70,329 PIP decisions that went to appeal were overturned in the claimant's favour.
Separate figures from the Motability charity show 67,000 people had cars on the scheme taken away as they transferred from DLA to PIP - 45% of all cases. Of these 4,500 rejoined the Motability scheme after the decision was overturned.
More than 2.4 million PIP decisions have been made, and of these 8% have been appealed and 3% have been overturned, in most cases because people have submitted more oral or written evidence.