Katie Davidson, 21, suffers from a range of mental and physical disabilities including autism spectrum disorder, attention deficit disorder, joint hypermobility syndrome, which causes her a lot of pain and restricted movement, panic attacks, depression and anxiety.

For the past two years she has been receiving £82.20 a week on the Personal Independence Payment (PIP) enhanced care rate as well as the standard mobility payment of £21.80 a week.

Her partner and full-time carer Martin Laird, 23, was also in receipt of £62.10 a week in Carer’s Allowance because she needs round-the-clock care.

However, after a DWP assessment, Katie got a letter saying that her PIP enhanced care payment has stopped and her partner would no longer get Carer’s Allowance to look after her, which means the couple are struggling to make ends meet on £87 a month.

The DWP said the reason for Katie’s benefit cuts was that she told the assessor she was able to carry out eight out of the 10 criteria and only had problems preparing food and engaging with people face-to-face. However, both Katie and Martin say this is not true and they did not say this to the assessor.

Katie’s mother Morag fears the distress of the DWP decision could push her daughter to the edge of despair.

Morag, from Livingston, West Lothian, said: “Financially it is an absolute nightmare for Katie and her partner, having to rely on crisis loans and food banks.

“The DWP have just taken her enhanced care away, they don’t care how she lives. They are not interested in her welfare or how she feeds or cares for herself.

“It is horrendous the way the DWP are treating people.

I am very concerned for Katie and I worry this will push her too far, but I’m trying very hard not to think about what that might mean.”

The family plans to pursue a “mandatory reconsideration” in a bid to get the decision reversed, and if that fails will have to go down the long road of appeals.

Mother-of-six Morag said: “Katie struggles with certain types of communication. She is OK with written stuff but has problems with auditory processing, meaning she struggles to process information that is given to her verbally. She has problems with sensory processing so she doesn’t like certain types of noises, busy places or people she doesn’t know, or any change and has periods where she doesn’t really ‘do’ people because she finds it overwhelming.

“It is a disability and that is why she was getting PIP, it is what is called a hidden disability because you cannot look at Katie and see that she is in a wheelchair or a stick because she is blind or anything like that.

“Katie needs someone there all the time. Because of her condition she struggles with motivation, she isn’t motivated to cook so unless prompted she just won’t eat, she needs someone to remind her to get up, get dressed and go to the toilet. She struggles to get in and out of the bath because of her restricted mobility. She is really bad at sleeping and if she’s not told to go to bed she would just stay up all night. She goes days and days without sleeping.”

Katie said she feels “helpless and stressed” over the DWP decision. “Losing the enhanced care component of my PIP and Martin’s Carer’s Allowance means we have no money left,” she said.

“We’ve already borrowed all we can from friends and family, and after realising we couldn’t afford to eat last week we had to go to a food bank. The appeal could take months and the uncertainty is only making me feel worse.

“It looks like I might have to apply for Employment Support Allowance (ESA), even although we were advised not to go down this route because of the further negative impact on my mental health.”

Social Justice Secretary Alex Neil promised when Scotland has control over disability and carers’ benefits, people will be treated with respect and dignity. “The process of applying and being assessed for benefits can be stressful for anyone, but for people with disabilities it can be a traumatic experience which can worsen their condition,” he said.

The SNP’s disability spokesperson Natalie McGarry MP described Katie’s story as “utterly heartbreaking”.

She added: “The Tories’ ideologically driven cuts to disability benefits will reduce PIP spending by 20 per cent, but behind these stark statistics are disabled people left to live in poverty.

“If the Scottish Parliament is to have the maximum flexibility to take a better approach, Iain Duncan Smith must halt the discredited reassessment process and devolve funding in full to the Scottish Parliament.”

Black Triangle, a Scottish disability campaign group, said the sooner Scotland gets full powers, the better to stop people suffering like Katie. Campaign manager John McArdle said: “We demand that power over welfare be devolved to Scotland, because it is killing our people.”

The DWP said that after a face-to-face assessment and consideration of all the medical evidence provided, Katie was found to be eligible for the standard rate for the mobility element only.

She was also found to be ineligible for the daily living element, which meant that her partner was no longer eligible for Carer’s Allowance.

A DWP spokesman said: “PIP helps with some of the extra costs caused by long-term ill health or a disability. It is not intended as an income replacement benefit such as Employment Support Allowance or Jobseeker’s Allowance.”