Footage shows detainee being choked at immigration removal centre

The incident forms part of an alleged culture of abuse captured by undercover filming at the Brook House facility near Gatwick Airport.

G4S, which runs the centre, confirmed last week that it had suspended nine members of staff pending further investigation.

The suspensions were announced ahead of the broadcast of a BBC Panorama probe on Monday night.

Footage allegedly shows staff mocking detainees who were receiving medical treatment after self-harming or taking drugs.

In one incident a detainee was self-harming by trying to self-strangulate and putting a mobile phone battery in his mouth.

A custody manager allegedly remarked: "Plug him in and he'll be a Duracell bunny."

It is claimed that later during the same incident, when the detainee was being physically restrained, another member of staff was filmed choking the detainee.

Panorama's undercover reporter said the staff member "basically stuck both of his fingers into his neck, and he was pushing so, so hard I could hear the detainee trying to gasp for breath".

The footage is said to reveal that drugs, particularly the psychoactive substance "spice", are rife inside the centre.

The programme also features an allegation that G4S management were warned three years ago about a group of officers mistreating detainees at Brook House.

The facility is one of two immigration centres run by G4S in the UK and has capacity for 508 adult men.

Those held at Brook House include foreign national offenders, asylum seekers and people who have over-stayed visas.

Jerry Petherick, managing director for G4S custodial and detention services in the UK, said: "The company investigates all complaints and has confidential whistleblowing channels for staff.

"There is no place for the type of conduct described in the allegations anywhere in G4S and it is not representative of the many G4S colleagues who do a great job often in difficult and challenging circumstances."