When Albert Thompson went for his first radiotherapy session for prostate cancer in November he says he was surprised to be taken aside by a hospital administrator and told that unless he could produce a British passport he would be charged £54,000 for the treatment.

Thompson has lived in London for 44 years, having arrived from Jamaica as a teenager, and although he has worked as a mechanic and paid taxes for more than three decades, the Home Office is disputing his eligibility to remain.

Official suspicion about his immigration status led to him being evicted last summer, and he was homeless for three weeks. His disputed status has also led to free healthcare being denied. Because he has no savings and no way of paying £54,000, he says he is not receiving the cancer treatment he needs.

The 63-year-old, who asked for his real name not to be printed on legal advice, is another victim of an unfolding scandal around the treatment by the Home Office of a group of people who arrived in the UK as children from Commonwealth countries. This cohort grew up believing themselves to be British, only to discover in a rapidly hardening immigration climate that they need documentary proof of their right to be here, which many do not have.

Thompson’s mother moved from Jamaica to the UK in the 1960s to work as a nurse, dedicating much of her working life to the health system. He married in Britain, and has two grown up sons and a 15-year-old daughter. Thompson was employed full time as a mechanic and later did MOT work, until 2008 when he was diagnosed with the blood cancer lymphoma; since then he has been too ill to work.

His problems with the Home Office became acute last July when he was evicted from council-owned accommodation because officials questioned whether he was eligible. The Home Office said it could find no record of him in its files and he was forced to sleep on the streets, until the homelessness charity St Mungo’s housed him. “I kept myself away from other people, sleeping around the back of shops. It was a bit frightening when you’re not used to it,” he said.

He had surgery for prostate cancer in January last year and was to begin a course of radiotherapy at the Royal Marsden hospital last November. But when he turned up for the appointment he was ushered into a side room by a member of staff for a discussion about eligibility and costs.

“I was expecting to get the treatment, but they gave me a form requesting a British passport, so that was the end of that,” he said. Thompson has never had a British passport, and was not aware he needed one. The Jamaican passport he arrived with was lost many years ago.

“The lady wasn’t at all polite. She said you have to produce it or pay £54,000. I said: ‘Oh my god, I don’t have 54 pence, let alone £54,000.’ I told her I’d been here all my life but it made no difference.” The Royal Marsden hospital have confirmed that is the cost of the treatment Thompson needs.

Thompson’s case has been taken up by the migration charity Praxis. Photograph: Jill Mead/The Guardian

Last October the Department of Health published new guidance highlighting NHS trusts’ legal responsibility for charging overseas visitors. A letter from the hospital stated unless Thompson could provide documents to prove that he was “ordinarily resident and legally entitled to live in the UK”, he would be required to pay for treatment “in full, in advance”.

Thompson has struggled to find enough evidence to satisfy the hospital and the Home Office of his status and is increasingly concerned about what effect the lack of treatment may be having on the cancer. “I don’t know what is going on inside; it is really worrying me. It feels like they are leaving me to die.”

Lawyers at the law firm Duncan Lewis are trying to help but because there is no legal aid for this kind of case, can only continue if exceptional funding is raised. His lawyer, Jeremy Bloom, said the firm had been contacted by a number of people encountering similar problems.

“The Home Office routinely fails to recognise people’s permission to be here, regardless of whether a person has been living in the UK, registered with numerous other government departments, paying taxes and contributing to society for decades,” he said. “This case is particularly serious because of his urgent health needs, and the time that it will take for him to regularise his status here through making the appropriate immigration application. Meanwhile, he is being denied potentially life-saving treatment.”

Thompson’s case has been taken up by the migration charity Praxis, based in east London. It has seen a sharp rise in cases involving retirement-age Commonwealth citizens who have lived continuously in the UK for about 50 years, but are facing questions about their immigration status, resulting in evictions, refusal of benefits and dismissal from work.

Before 2015 the relatively small charity kept no record of the cases. In 2015 it dealt with 20, in 2016 there were 39, in 2017 there were 54 and since the start of this year the charity has already dealt with 13.

“The numbers are galloping up – these are people who have paid taxes and contributed all their adult lives who are suddenly being stopped and asked: on what basis are you here?” said Bethan Lant of a Praxis. “Their only crime is that they have not filled in a form from the Home Office.”

There is growing awareness of the problems faced by long-term UK residents who do not have the paperwork to prove they are in the country legally. Last year, Paulette Wilson, 61, a cook who had worked in the House of Commons, narrowly avoided deportation to Jamaica, where she was born.

Thompson’s situation is not unique. Lawyers at Southwark Law Centre are fighting a similar case involving a man who arrived as a child more than 40 years ago from a Caribbean country who has also been told that he is not eligible for cancer treatment on the NHS. As a result of the Home Office decision to question his immigration status, he is living on local authority destitution support – having paid tax and national insurance for decades. After a legal challenge, he has received some treatment but he has been told he must pay for it.

Thompson is feeling unwell and is constantly worrying about his condition, his treatment and his Home Office status. “I’ve got no money. Since I stopped work when I got ill I’ve been living from day to day,” he said. “I’m very angry with the government. I’m here legally but they’re asking me to prove I’m British.”

A spokesperson for the Royal Marsden said: “Each NHS Trust in England is legally responsible for identifying and charging overseas visitors using NHS services where the patient cannot prove that they are ordinarily resident and legally entitled to live in the UK. In line with Department of Health guidance, from 23 October 2017 the Royal Marsden is now legally required to charge non-eligible patients in advance of any treatment.”

