It’s fair to say Grant Borner knows a thing or two about computers. He was a mainframe operator, responsible for checking his firm’s processing systems, before he was made redundant in 2017. Yet even Borner struggled to complete his online application for universal credit when he was moved on to the government’s flagship benefit scheme last year.

“Not having the internet at home is a nightmare. I had to stop it to reduce my bills,” he says. “I went around to my parents’ house and used theirs but I got timed out after 45 minutes – I lost everything. I tried it several times but it wasn’t having it.”

Borner had to go to the job centre in Harlow on four different occasions that week to complete his application for the digital-by-default benefit, which combines six different payments into one. The delay meant the 57-year-old had to wait even longer than the then six-week delay for his first payment and was forced to use a food bank. “Without that food bank I wouldn’t have had a thing,” he says.

Borner’s struggle is far from unusual. The Department of Work and Pensions’ (DWP) own survey data suggests 46% of people claiming universal credit need help applying online. The same data shows that a quarter of applicants who fail to submit their claims online put it down to difficulties accessing computers or the internet.

The government expects people to make and manage their claims online, but last year the UN’s rapporteur on extreme poverty, Philip Alston, noted that just over half of people on low incomes in the UK do not have home broadband and 21% of the entire population do not have basic digital skills. Alston said the digital-by-default design of the universal credit system may be contributing to the third of claims never reaching payment, and accused ministers of putting up digital barriers “that effectively obstruct many individuals’ access to their entitlements”.

Borner is still living with the consequences of that traumatic week, as he is paying off a loan from his job centre which he took out to cover his bills. This leaves him £292 a month. After bills he has about £2 a day for essentials like food. “I have to scrounge off my parents – they feed me,” he says. “I’m 57 years old and I should be looking after those pair of poor old sods. He’s 81. She’s 78.”

Borner also has to go to his parents to manage his claim, which requires claimants to record 30 hours of job hunting every week in an online journal. If he fails to update his journal he risks being sanctioned and having his benefit cut. “It’s a worry because I don’t have the internet at home,” he says.

Charities warn such digital requirements could have serious implications for 3 million existing claimants, including thousands unable to work because of disability or illness, due to be moved over to universal credit from 2020. Initially, 10,000 people will be transferred in a pilot starting this July. They will then be followed next year by millions of people claiming disability and unemployment benefits.

Mental health charity Mind is concerned that vulnerable claimants may be left penniless when they have to make claims online, as the government has refused to transfer people over to the new system automatically. “There is a risk that if you fail to make a claim in the time window there is nothing to stop you losing your money altogether,” says Paul Spencer, Mind’s policy and campaigns manager.

The DWP itself says chronically ill people are more likely than other claimants to struggle with applying and managing their universal credit claims online. The department’s 2018 report showed that nearly 40% of people with long-term health conditions find the application process difficult and 53% need ongoing support with their claims.

Spencer says the system has not been designed to take into account the barriers people face. “Too many people do not have access to computer or to the internet to make a claim.”

Problems don’t end once people have applied. Citizens Advice, which will be providing advice to universal credit claimants from April under a government scheme, says the benefit doesn’t take into account people’s actual circumstances.

“People are expected to monitor their online journals in almost real time. They get notifications for meetings and instructions in their online journals,” says Kayley Hignell, Citizens Advice head of welfare policy. “But many of our clients don’t have the internet at home or lack digital skills and may not get these messages. They then run the risk of getting sanctioned.”

Spencer says these threats can exacerbate illnesses and stop people applying for help. “The cumulative effect is that it sets people back. People are being made unwell or dropping out of the benefit system.”

Sixty-one-year-old Anne-Marie, who has been struggling with depression for 20 years, was told to apply for universal credit at the end of January when her husband, who has dementia, was taken into a care home in Oxfordshire. However, she had to seek help from her local Mind branch because she has few computer skills and cannot afford an internet connection.

“I’m absolutely hopeless on computers,” she says. “Applying was awful. We started at 11 in the morning and eventually we got through at 2 in the afternoon because the computer kept on crashing.” Out of desperation she phoned the universal credit helpline and was given an appointment at her job centre, where she was finally added to the system. She now has a five-week wait for any money.

“For the first time in my life I went to a food bank last week. It was humiliating for a woman of my age to go to a food bank,” she says. “I was never brought up to go begging or live off the state. I was told to make your own way in life.”

Despite lacking even a smartphone, Anne-Marie is expected to manage her claim online. “I’m getting anxious. If you don’t fill in your journal you get sanctioned and then how do I pay my rent? That makes you feel closer and closer to becoming homeless.”

Former railway trackman Josh, who hasn’t been able work since he had a serious heart attack and stroke three years ago, was told to apply for universal credit when his disability benefit was wrongly stopped.

“You are meant to go on online and do things which I find impossible. I cannot fathom it to be honest with you. I’m on such a low amount money I cannot afford the internet. I’ve got a really bad phone. I run out of 3G all the time,” says Josh, who lost 20% of his brain function in the stroke.

He says it is difficult for him to get online elsewhere. “I’m in a village. There isn’t any library in three miles of here,” he says. Josh has had to rely on his sister and girlfriend. “If they weren’t there to help me then I would probably be homeless by now. I needed them to do the online stuff because I couldn’t do it myself.”

The DWP insists people without internet access can use thousands of free computers in job centres and public libraries. It says applications can be made in person or on the phone. “Around 98% of people claim online, and the majority found the process easy,” says a spokesperson.

This doesn’t reassure Anne-Marie. She worries she won’t be able to survive on universal credit. “I don’t know whether I will be around in five years. I might end my life because the way things are going.”

* Some names have been changed

• In the UK, Samaritans can be contacted on 116 123 or email jo@samaritans.org. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In Australia, the crisis support service Lifeline is 13 11 14. Other international suicide helplines can be found at www.befrienders.org.