Mark Harper, the minister for disabled people, will appear in front of the work and pensions select committee on Wednesday today to defend the government’s troubled record on implementation of the new disability benefit, the personal independence payment (PIP).

He will be hoping that the session goes more smoothly than last June’s hearing on the same subject by the public accounts committee when its chair, Margaret Hodge, said the launch of the new assessment system had been “nothing short of a fiasco” and accused the government of letting down “some of the most vulnerable in society”.

Over the past year, charities have highlighted the enormous distress experienced by people who have faced serious delays in being assessed, with some facing waits of up to 14 months for the benefit to be paid. New statistics detailing whether the Department for Work and Pensions has been successful in meeting a 16-week target for the benefit to be assessed will be released on Wednesday today.

The problems with processing the benefit, which replaces the old disability living allowance (DLA), echo ongoing issues with the rollout of employment and support allowance (ESA), which have also provoked profound unhappiness from disability groups. Harper is the fourth minister for disabled people in this parliament – a troubled brief, presiding over some of the most controversial coalition policies; like his predecessors he can expect to face tough questions from MPs on the committee.

An independent review of PIP by Paul Gray, chair of the social security advisory committee, published before Christmas, described the process of introducing the benefit as “a major delivery challenge”. The review heard from many people who had claimed PIP, and the overwhelming theme was “the impact of delays and backlogs”.

The assessment is not a “precise science”, the report said, adding that “accurately and consistently assessing several million awards in this way is a formidable undertaking”, and concluding that the current process is “disjointed”.

PIP is intended to provide financial support for disabled people with the greatest challenges to remaining independent and is paid to people in and out of work, aged between 16 and 64, to help with some of the extra costs caused by long-term ill-health or disability. Payment ranges from £21.55 to £138.05 a week depending on how the condition affects the claimant. Assessments have been outsourced to Atos, the IT firm that is ending prematurely its parallel contract for assessing ESA claims this spring, and outsourcing giant Capita. The select committee will also scrutinise their performance today.

Disabled woman protesting against Atos assessments. Photograph: Julian Makey/Rex Features

A spokesman for the Department for Work and Pensions (DWP) says improvements to PIP had already been made, adding: “Between January and October 2014, the number of claims processed increased fourfold to 66,000 per month, and we are working hard to continue to make further improvements.” The independent review also noted that improvements had been made to speed up the processing of claims for people who are terminally ill.

But charities have opposed the DWP’s decision to continue rolling out the benefit, after pilots around the country, despite the fact that the current system has built up a huge backlog of claims and left many disabled people waiting for over six months, and in some cases a year, for their claims to be processed. Earlier this month, Citizens Advice in Scotland called on the government to halt the introduction of PIP there.

The delays are categorised by the MS Society as unacceptable. “People with disabilities have found themselves in extreme financial hardship as a result of the delays; isolated and unable to access the support they need, like transport to hospital appointments, or help around the home. Not having an answer on PIP makes it much harder to claim other important benefits like carers’ allowance, the blue badge, disability premiums on means-tested benefits and working tax credit,” says a MS Society spokeswoman. “We have been shocked to find that despite the delays, some disabled people could be forced to go through another assessment for the benefit years before they were originally told they would have to reapply.”

Macmillan Cancer Support describes the system as “riddled with delays”, and said in December, in response to the independent review, that it was “a disgrace that thousands of people with cancer have been forced to wait six months or more just to find out whether they were even eligible for the disability benefit… What we are seeing is failure in the system that is having a very real and shattering impact on the lives of people with cancer”. A recent survey of Macmillan benefits advisers revealed that 30% knew of someone who had died waiting for benefits to be processed.

The most challenging phase of reassessment of most current DLA recipients is scheduled to begin from October.

In April 2013, the DWP predicted it would take around two and a half months to reach a decision for non-terminally ill people and 10 days for people with a terminal illness. Last year, the National Audit Office noted that the time for making a decision was 28 days for claims by the terminally ill and around three and a half months (107 days) for everyone else. These times have improved, but there is concern from Labour that the government has shifted the goalposts, in its 16-week target for an assessment(ie not a decision or a payment); an earlier target said it should take 12–16 weeks for a decision to be made.

The benefit was designed to cut costs, but the Institute for Fiscal Studies calculated last year that “significant delays” in the replacement of DLA with the “less generous” PIP had led to a £1.6bn increase in spending, rather than a £1.2bn cut. However, the DWP says it is now on course to make “significant long-term savings” of an estimated £2.5bn, against previous predictions. It also said that nearly 22% of applicants are now getting the highest level of support under PIP, compared to 16% under the previous DLA system.

Kate Green, Labour’s shadow minister for disabled people, says the policy was “costing more, damaging people’s lives and not delivering what the government claimed it would. The impact on disabled people is acute with families left for months without support. The DWP have continually shifted the goalposts and it remains far from clear whether the new 16 week deadline to get a PIP assessment has been met. Disabled people, families, carers and welfare advisers in touch with my office say people are still waiting for longer than 16 weeks.”

Lawyers at Irwin Mitchell Solicitors have been applying for a judicial review into PIP delays, acting on behalf of six clients who had been waiting between seven and 14 months when they approached the firm for help. The application for judicial review was refused last week, on the grounds that the application was “academic”, because the benefit had already been approved. The firm notes that the DWP resolved these cases very swiftly once the application for judicial review was received, making it impossible for the case to proceed.

Anne-Marie Irwin, a lawyer at Irwin Mitchell says: “We are concerned with the delays in dealing with PIP applications and are worried that DWPs approach in fast-tracking our clients that are taking legal action is ignoring the thousands of others who are awaiting a decision on their payments.

“PIP was created to ensure that the thousands of vulnerable people across the UK are able to get support for extra costs caused by long-term ill health or disability. We hope that the select committee makes clear recommendations to ensure that decisions are made by the DWP in a reasonable time. Too many people are experiencing unnecessary and unacceptable delays as they need this support to be able to meet the additional costs which arise as a result of their disability. This issue has left our clients struggling to cope financially, with the strain and stress of these issues also having a significant impact on their health and wellbeing.”During an adjournment debate on PIP last week, MPs detailed the unhappy experiences of some of their constituents, as they have waited for their claims to be processed.

They heard about a student nurse who works part time as a chef, who said she had been forced to sell her house as a result of the PIP assessment waiting time, expected to be around 26 weeks. They also heard about Malcolm, who applied for PIP in March 2014 when he was diagnosed with cancer, but who has still not had an assessment; the delays have affected his ability even to travel to and from hospital for appointments.

Claimants report feeling confused about who is responsible for the process, being told by the assessor (Atos or Capita) to contact the DWP, and vice-versa – a confusion that echoes the ongoing muddle over ESA. Internally, there are reports of similar attempts to pass the buck between the ministry and the companies, when attempts are made to analyse who is responsible for the delays.

In a written statement, Stephen Duckworth, head of Capita’s PIP programme, said he “wholeheartedly apologised to those who experienced delays”.

“PIP was an entirely new benefit and with that comes a number of unknowns. Capita and the DWP now have a better insight into what is required and, as such, have made significant changes across PIP – increasing the number of assessments carried out and not compromising on quality,” he said.

Atos said it did not wish to comment about its performance in implementing PIP assessments.

‘As a benefit claimant, you are presumed guilty of fraud

Penny Tyas, 57, who has multiple sclerosis, faced delays in payments that led to her being evicted and being declared bankrupt Photograph: Roddy Grimes-Graeme

Penny Tyas, 57, a former accountant from Lymington, Hampshire, was diagnosed with multiple sclerosis in the summer of 2013 and applied for PIP immediately. She filled in the form for the benefit in June, but did not receive her first payment until January 2014. In the intervening period she had been rejected for the benefit by Atos assessors, and the long delay contributed to a serious decline in her financial situation; she got into debt, was evicted and declared herself bankrupt.

At her lowest point, she and her 14-year-old son were surviving on food bank parcels and she was left with just 22p. She has kept those remaining coins and plans to turn them into jewellery to remind her of that “dire” time. “2013 was not a good year,” she says. She found the process of applying for the benefit exceptionally stressful, which caused a decline in her health. “You have to describe in detail the effect of your incurable, degenerative disease, and you know how much rests on the decision,” she says. She was asked if she could walk 50m. “I have been known to walk 100m, but I can’t walk that distance quickly, safely or as often as necessary,” she says. After the assessment, she was puzzled to discover that she had been judged capable of walking 200m, although no one had asked her to walk at all. She was refused the benefit. “In the UK you are meant to be innocent until proven guilty, but as a benefit claimant, you are presumed to be guilty of benefit fraud until you have proven over and over again that you really are a genuine case”, she says.

“Personal independence payment is not meant to be used to live on but to retain some independence,” she says – helping to pay for taxis, for shopping deliveries, for help at home. Without it, she was ineligible for other related benefits – discount railcards, free road tax, shopmobility services. Although it isn’t meant to be for living expenses, at the time her basic benefits were swallowed repaying debt she had got into when her condition was diagnosed, so the absence of the money was felt acutely.

While she waited her situation worsened. She wasn’t paying rent, got an eviction notice, and faced homelessness until she and her son were rehoused by the council. When she (repeatedly) rang Atos to ask when she was going to be assessed, she was told they couldn’t say.

She is angry that the diagnosis by neurologists of her incurable condition was not considered sufficient evidence for Atos to grant her the payments, until she launched tribunal proceedings. When they were finally granted, her payments were backdated, but she points out that retrospective payments aren’t very helpful if you don’t have anything to live on in the meantime. Her award was meant to continue until September 2016, but in August she was told she must reapply and was forced to go through the bureaucratic process again in order to secure her payments.