Campaigners protested outside the Dungavel immigration detention centre in Scotland on Saturday.
Some 30,000 people a year are detained indefinitely at “immigration removal centres”. But the centres have come under scrutiny.
G4S, the private company that runs the Brook House detention centre near Gatwick airport, has reportedly commissioned an independent review into its running of the centre.
Undercover footage obtained by the BBC showed guards “mocking, abusing and even assaulting detainees”.
Brook House boss Ben Saunders previously ran Medway children’s prison for G4S before it dropped the contract after abuse and corruption was exposed.
This follows a damning prison inspectors’ report into the Yarl’s Wood detention centre last week, and calls for MPs to abolish indefinite detention.