A man has died while in detention at the Brook House migrant removal centre in West Sussex, the company that runs the centre has confirmed.
Security firm Serco said a 26-year-old man died at the facility, which is located next to Gatwick Airport, on Sunday.
The Home Office said its condolences were with the man’s family and friends.
Migrant removal centres house a range of detainees, including asylum seekers, people who have been refused the right to remain in the UK, or people awaiting deportation after completing a criminal sentence.
There is currently no maximum period for which detainees can be held.
A public inquiry into the centre last year described a toxic culture in which migrants were subjected to degrading treatment and the inappropriate use of force.
The public inquiry was launched following an investigation by BBC Panorama in 2017 prompted by a whistleblower who worked as a custody officer at the centre.
The final report identified 19 incidents of mistreatment against detainees over a five-month period in 2017.
They included unnecessary pain inflicted on four detainees, dangerous restraint techniques, and the forcible moving of detainees while they were naked or near naked.
The report also said detainees had been the targets of racist, homophobic, and humiliating language.
The centre itself was found to be overcrowded, dirty, and noise from aircraft at Gatwick, while there was also widespread use of the so-called zombie drug Spice.
In August, a further report by the Gatwick Independent Monitoring Board, which monitors the centre, found “continuing failings”, and last month Kate Eves, who chaired the public inquiry, said the government had agreed to implement only one of her 33 recommendations.
The Home Office has previously said it is “committed” to improving immigration detention facilities.
In a statement, charity Gatwick Detainees Welfare Group compared Brook House to a prison and said “no-one should take their last breath there”.
“We mourn that a young man died before he could be free,” it said.
Amnesty International UK’s refugee and migrant rights director, Steve Valdez-Symonds, called the death a “tragedy”.
“Brook House has gained notoriety for violence, racism and abuse,” he said.
“What part this may have in this man’s death we do not yet know, but these degradations derive from a wider failure to make a system respect human dignity and rights.
“Tragic incidents such as this emphasise why the government must bring humanity to the immigration system as much as any other policy area – people’s lives depend on it.”