31 October 2012 Last updated at 18:59
"An inquiry is under way into the death of a detainee at the Harmondsworth immigration centre in west London, the UK Border Agency (UKBA) said.
It is believed the male, who has not been named, collapsed on Tuesday after being restrained at the centre near Heathrow Airport.
The investigation would be conducted by the Prisons and Probation Ombudsman.
The centre is run by a private firm, the GEO Group UK Ltd, which has so far not responded.
The detention facility in West Drayton holds 615 men who are awaiting removal or deportation from the UK.
A UKBA spokesman said: "This death is being investigated so it would be inappropriate to comment at this stage.""
Last Updated on Wednesday, 31 October 2012 22:29