A Nigerian man said to be "near death" following a hunger strike is back in the UK after the Home Office flight deporting him had to turn around.
Lawyers for Isa Muazu, who has refused food for "over 100 days", said he had returned to the medical wing at Harmondsworth detention centre.
Mr Muazu had sought asylum in the UK claiming he would be killed by Islamic extremists if returned to Nigeria.
The Home Office rejects his arguments and attempted to deport the 45-year-old on Friday after he lost a series of legal challenges.
The privately-chartered jet carrying Mr Muazu was in the air for a number of hours, but it is believed the Nigerian authorities did not give the pilot landing rights. It is unclear why.
The plane is thought to have stopped in Malta for two hours before returning to the UK.
The Home Office refused to comment on the latest developments, but it is understood officials are working with the Nigerian government to try to secure Mr Muazu's removal.
He has been held in detention since he claimed asylum in July, saying he faced persecution from the hardline Islamic group Boko Haram.
Mr Muazu entered the country on a visitor's visa in July 2007 and stayed without permission after it expired in January 2008.
It is believed he then found work in south-east London and was detained on the day he claimed asylum, 25 July this year.
Duncan Lewis Solicitors, representing Mr Muazu, said his case was then fast-tracked and his application was rejected in August.
They said he had made himself "seriously ill" in his protest, adding: "His hunger strike lasted for over 100 days".
A claim that his detention was unlawful was rejected by the Court of Appeal on 25 November, and two further last-minute appeals were also refused, his lawyers said.
Lord Roberts, a Lib Dem peer, told the Observer newspaper he had seen Mr Muazu on Tuesday "when a doctor had judged him too ill to fly".
"Goodness knows what state he must be in now, the poor man," the peer said. "He needs hospital treatment.
"[Home Secretary Theresa May] has caused immense harm to one individual and spent an extraordinary amount of taxpayers' money.
The Nigerian is 5ft 11in (1.8m) tall, weighs eight stone (53kg) and has described himself as "looking like a skeleton", his lawyers have said.
He has said that he came to the UK "for a better life" and would "rather die" than face removal.