Abi, 20, from Estonia [...] was travelling alone for the first time to stay with family friends in Britain, and asked that the Guardian use a pseudonym.

“First they asked what I was doing in the UK and I said that I was visiting family friends,” she said. “After that they asked me the same question again, as if it was not the right response. Then I said I would be helping to watch their kids. So they immediately assumed that I was going to work as au pair.”

She was accused of intending to work as an au pair and was locked up in Gatwick for 30 hours before being expelled at the end of last month. During her detention, she said, she had several panic attacks, vomited from fear, and was not allowed to retrieve a sedative from her luggage.

Wolfgang, a German national who runs an IT business, was detained at Heathrow airport despite having proof of settled status, indefinite leave to remain and a British passport on the way.

He is furious that his rights were suspended on the whim of a Border Force official.

“I have settled status,” he said. “I have indefinite leave to remain. I am about to become a British citizen. How is it that a border official with one tick can suspend those rights?”

“To be blunt, I am avoiding coming back to the UK now until I get my British passport,” Wolfgang said from Germany. “I pay a large amount of tax there, I have never used the health service, I contribute to the economy, I own property there. London is my favourite city in the world, but I have no documents to show I can stay there,” he said, referring to the fact that the government has voted against giving EU citizens a residency card to show employers, landlords or border officials.

Among the other cases is that of Antonio, a Spanish airline worker who was made to wait for 45 minutes at Gatwick while border officials tried to decide if he was lying when he told them he had pre-settled status.

He said: “My passport was not associated with the settled status. When I told them that is because I applied using my ID card which was perfectly acceptable to the Home Office, they told me that ID cards are no longer acceptable at the border.”

He was only let through after he produced his airline ID and his flight-attendant schedule to prove he was not an illegal migrant.

“Because of my job I have flown to many destinations and I have been through border controls in different countries. I felt I had landed in some random enemy state.