The 78-year-old British widow threatened with removal from Sweden after 21 years has said she has been left feeling sick with worry after being told she had lost an appeal against deportation in a ongoing row over the country’s handling of Brexit.

“I am in shock. I feel sick. An individual’s life is at stake at my age. It is hell. I have done nothing wrong. I don’t take anything from this country. I am self sufficient, I put money in this country, have no criminal record,” said Joyce Thomas from her home in Sweden on Thursday.

Her plight, first revealed by the Guardian, has raised concerns in Brussels and in the UK about Sweden’s approach to the EU-UK withdrawal agreement, which was supposed to protect British nationals who lived in an EU member state before Brexit.

Earlier this week another family told how their father, a dementia patient in full-time care, was also threatened with removal after 25 years in Sweden.

The administrative court in Luleå upheld Sweden’s migration agency decision that Thomas was not eligible to stay because her application was made in 2023, after the cut-off date of December 2021.

Her legal representatives told the court in Luleå it was “not proportionate for her to be deported solely because she missed a deadline due to insufficient information. Furthermore, it is not acceptable that the Swedish authorities failed to inform her that she needed to file an application and of the deadline by which it was to be filed.”

Thomas now faces the prospect of a letter from the migration agency giving her four weeks to leave voluntarily , separating her from her son, her grandchildren, her network of friends, and away from her husband’s grave, which she regularly visits.

If she fails to comply, not only will she face a forced deportation, but the court of appeal has told her she could face a “re-entry ban” and “registered on a watchlist” preventing entry into a Schengen country, which includes Sweden “as long as the re-entry ban remains in effect”.

“No circumstances have come to light that would lead to a determination that, in your situation, you are particularly vulnerable,” the court ruling said noting that she had lived most of her life in the UK, had a pension from the UK and another son in the UK.

Thomas argued that after 21 years all her support network was in Sweden, with 23 people including doctors, priests and friends and fellow churchgoers writing to testify in support of her case.

“My friends, my husband’s burial place, grandchildren, everything is here, and to have to go and start again, it’s just unbelievable that at my age I’ve got to be uprooted for my home,” she said.

“This is hell. I get up in the morning, it’s in my head, I go to bed at night, it’s in my head. It’s horrible. I mean I have done nothing wrong. I am self sufficient. I put money in the country. I don’t take money out. I can’t comprehend this,” she added.

Her husband died in 2023 from cancer just four months after his last trip back to the UK to visit family. It was on the return that he learned from border officials that they had to make a special application to stay after Brexit.

Under article 18 of the EU-UK withdrawal agreement, late applications are permissible if there are “reasonable grounds” for doing so.

David Milstead, of the grassroots campaign group British in Sweden, said: “It would be difficult to find anyone who would argue that what is happening to Mrs Thomas and others in Sweden was an intended outcome of the withdrawal agreement. Problems will inevitably emerge when a new treaty is put into practice. However, the UK, EU and Sweden must act to address them. Words and expressions of concern won’t cut it.”

While the migration agency said not knowing an application was needed was not a “reasonable ground” for granting post-residency rights, Thomas is adamant neither she or her husband were notified that an application needed to be made before the end of 2021.

“The Swedish authorities have our ID cards, they have our emails, we heard nothing,” said Thomas.