A frightened father hit the bosses after his severely handicapped son was checked to see if he was eligible for payments – despite being unable to move, eat or see him.
John McMullan, 50, said he was "amazed" by an assessment of his 26-year-old Declan, who suffers from blocked syndrome.
The assessors from Capita's private company insisted on calling Declan, from Crossgar to Co Down, Northern Ireland.
They are hired by the Local Department of the Communities to check if the applicants qualify for the Personal Independence Pay – which replaces the living allowance for the disabled.
The Captain's Worker then began a series of "ignorant questions," John asserts – and at some point he is supposed to have insisted on seeing Declan face to face.
John said the evaluator showed the "total ignorance" of his son's condition, about which physicians similar to "buried alive" said.
Speaking with Belfast Live, he added: "In my opinion, we have provided ample evidence of Declan's handicap, but I doubt they actually understood what is on that paper.
"I do not think the evaluators are prepared to do so."
Declan remained deactivated after a heart attack seven years ago, during which oxygen was interrupted to reach his brain.
He was eventually approved to receive the new PIP payment, but John was astonished to see that he had not received full grades for his daily needs.
John declares: "Declan can not eat and is fed PEG yet the evaluator gave him only 6 out of 10 for the level of assistance he needs with food and drink.
"He can not move at all, just blink, but the evaluator gave him only two out of eight points if he needs supervision or support for the management of therapies.
"He received 2/8 because he needed help in making budget decisions and only 4/8 because he needs support in social situations."
John added, "I knew that Declan would never be denied to PIP. It was just the stupidity of the trial and the fact that he did not even get complete points.
Declan is probably one of the most disabled people in Northern Ireland. How do you have to be invalid?
A Department of Commerce spokesman said: "The Department expects the highest standards at Capita, which delivers the PIP Assessment Service and must adhere to a rigorous set of quality standards set by the Department.
"Each disability assessor must have at least two years after the registration experience to be completed in an approved health care profession and be extensively trained in line with the DFC guidelines before conducting PIP assessments.
"The Captain is committed to providing a high-quality and empathetic service for PIP-seekers.
"Disability assessors are health professionals with the skills and knowledge to conduct PIP assessments in Northern Ireland.
"The PIP assessment looks at how individuals are able to complete a series of day-to-day key activities." Within each activity there are a number of descriptors, each representing a different level of ability to carry out the activity.
"Individuals receive a score for each activity, depending on how well they can do and the help they need to do that, which is based on the evidence provided and collected.
"The guidelines expected to be applied by disabled assessors and PIP cases managers are outlined in the PIP Evaluation Guide.
"There is a solid complaint process for customers who are not satisfied with the service offered by Capita, which includes the possibility of climbing a complaint to the Department if it considers that it has not been resolved satisfactorily.
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"Terms and conditions of employment contracts for disabled assessors are a problem for the Capita and are not established by the Department.
However, the Department understands that a 3,000-pound annual quality incentive is entirely based on a disability peer who produces consistent, high-quality reports in a timely manner and has nothing to do with PIP right decisions.
"Decisions on the rights of PIP individuals are taken by the Department.
"Each claim is considered individual and decisions are made on the basis of available evidence and relevant legislation.
More people are awarded PIP at the highest benefit rate than under the DLA.
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