Paulette Wilson had been in Britain for 50 years when she received a letter informing her that she was an illegal immigrant and was going to be removed and sent back to Jamaica, the country she left when she was 10 and has never visited since.

Last month, she spent a week at Yarl’s Wood detention centre before being sent to the immigration removal centre at Heathrow, where detainees are taken just before they are flown out of the country. It was only a last-minute intervention from her MP and a local charity that prevented a forced removal. She has since been allowed to return home, but will have to report again to the Home Office in early December and is still worried about the possibility of renewed attempts to remove her.

The experience of being detained and threatened with deportation to a country she has no links with has been profoundly upsetting for Paulette, a grandmother and former cook, who has paid national insurance contributions for 34 years and can prove a long history of working and paying taxes in this country.

Paulette, 61, arrived in the UK in 1968, went to primary and secondary school in Britain, raised her daughter, Natalie, here and has helped to bring up her granddaughter. For a while, she worked in the House of Commons restaurant overlooking the Thames, serving meals to MPs and parliamentary security staff. More recently, she has volunteered at her local church, making weekly meals for homeless people.

She has been left furious and distraught by this sudden Home Office decision to categorise her as an illegal immigrant. The week of detention in Yarl’s Wood was the worst experience of her life.

“I felt like I didn’t exist. I wondered what was going to happen to me. All I did was cry, thinking of my daughter and granddaughter; thinking that I wasn’t going to see them again,” she says while sitting in Natalie’s flat in Wolverhampton. She was taken from the Home Office reporting centre in Solihull, Birmingham, in a secure van and told she was going to be sent out of the country. “I couldn’t eat or sleep; still now I can’t eat and sleep properly.”

When staff told her after she had spent a week in Yarl’s Wood that they were going to take her to the removal centre, she was allowed to call Natalie; she screamed in terror down the phone. “I was panicking because that evening they took away a lady. I watched her crying and being taken away. It was very scary,” she says.

Paulette’s solicitor, Jim Wilson, is working to persuade Home Office staff that Paulette has a legal right to stay in the UK because she moved here before the 1973 Immigration Act gave people who had already settled in Britain indefinite leave to remain. Although the decision to detain and remove her is extremely unusual, there is evidence that a large number of people who came legally to the UK in the 60s have found themselves wrongly caught up in the “hostile environment” Theresa May said she wanted to create for illegal immigrants in 2012.

Migrant rights charities around the country are increasingly coming across people who have been living here for 50 or more years – often people from the Commonwealth – who came to the UK when there was no need to apply formally for leave to remain. They have only recently encountered problems because they have no documents to prove their right to be here. (Newer arrivals, who came after immigration laws became tougher and less welcoming, are less likely to find themselves in Paulette’s situation.)

All I did was cry, thinking of my daughter and granddaughter

In a separate case earlier this month, an urgent appeal was made to trace former pupils of a school in Maidenhead, to see if they could help save a homeless woman who also faces deportation. Eleanor Rogers, 71, arrived in Britain from Sierra Leone in 1966 and has lived and worked here since. She has lost her documentation and she, too, faces removal back to a country she hasn’t lived in for 51 years unless she can find people who can help prove she has been here for five decades. In a report, Chasing Status: If Not British, Then What Am I?, immigration advisors warn of a “virtually invisible and rarely acknowledged group who can’t easily prove their legal status”, who are surprised to find their right to live in the country where they have lived all their adult life being challenged.

When she was 10, Paulette’s mother put her on a plane to the UK, to live with her grandfather, a factory worker, and her grandmother, a care worker. Her mother, who she never saw again, sent her here for a better life and, on the whole, Paulette has been happy here. She never travelled back to Jamaica and never applied for a passport. She never gave a thought to her immigration status.

Paulette Wilson with her daughter, Natalie. ‘They have put me through the worst heartache anyone could go through.’ Photograph: Fabio De Paola/The Guardian

In 2015, she was shocked to receive a letter informing her she was an illegal immigrant and that she had six months to leave the country. For a few days, she told no one. “I was panicking. I was too scared to tell my daughter,” she says.

Her housing benefit and sickness benefits were stopped immediately, leaving her homeless. For two years, Natalie has been supporting her financially and a friend has let her stay in his flat. She was told to report monthly to the Home Office.

Natalie and her case worker, Daniel Ashwell, at the Refugee and Migrant Centre in Wolverhampton have gathered documents proving that she has been in the country for 50 years. Paulette’s grandparents struggled to look after her for a while when she was in her teens and they sent her to a children’s home. The family now has letters from Shropshire council, acknowledging that she was there in the 70s. Her case worker believes there has been some bureaucratic confusion on the part of the Home Office, and a lack of understanding among junior staff about the law making it clear that Paulette has the right to remain.

“They have deprived her of everything,” Natalie says, detailing how her mother has been near destitution for the past two years. “I am surprised we didn’t lose her from the stress. She is normally so bubbly and sociable. Since she came out of Yarl’s Wood she has withdrawn.” A few times in the last month, Paulette, who lives nearby, has come to her flat in the middle of night, waking her to tell her she is scared that Home Office workers are going to come to take her away. She can’t sleep until she gets into Natalie’s bed. “I feel very angry. They have put me through the worst heartache anyone could go through,” she says. Paulette’s MP, Labour’s Emma Reynolds, says: “It is really shocking that the Home Office is detaining a woman in her 60s who has been here for 50 years. It seems to me that Paulette Wilson was detained wrongly and I am seeking clarification from the Home Office. My understanding is that she is here legally.”

Her solicitor, Jim Wilson, who volunteers legal support to the Refugee and Migrant Centre, says he knows of a number of people in a similar situation, but no one else who had been detained and threatened with removal.

We see time and time again that people are placed in detention only to be later released

Unusually, Paulette was not given a document giving details of the Home Office’s decisions when she was released from detention. Ashwell, her caseworker, says he has requested it several times, but has had no response. He says he has dealt with as many as 40 similar cases of people who have lived here for decades, but do not have British citizenship. “It’s very hard to communicate with anyone in the Home Office,” he says. “It’s hard to get through on the phone and you never speak to the person making the decision because those numbers aren’t provided. You’re always talking to an intermediary.”

Satbir Singh, chief executive of the Joint Council for the Welfare of Immigrants is also troubled by her case. “Paulette is part of this country, part of her community and she belongs here,” he says.

He also expresses concern about the week Paulette spent in detention. “It is unlawful to put someone in detention without a realistic chance that they will actually be removed. We see time and time again that people are placed in detention only to be later released. This inflicts huge trauma on individuals who may have done nothing wrong, at a shocking cost to the taxpayer.”

In a response to Paulette’s MP, a member of the Home Office “account management team” wrote: “It may help to explain that Ms Wilson currently has no legal basis of stay within the UK and is liable to detention or removal.” The Guardian has approached the Home Office for further comment.

Paulette is despairing at the pressure she is under to prove that she is British. The application to process leave to remain documents costs more than £240, money she does not have. Legal aid is no longer available for cases such as hers. She is terrified that she could be separated from her family. “I don’t know anyone in Jamaica. I had no passport so I couldn’t go,” she says. Paulette does not like to be asked if she feels British. “I don’t feel British. I am British. I’ve been raised here, all I know is Britain. What the hell can I call myself except British? I’m still angry that I have to prove it. I feel angry that I have to go through this.” AG