The death of a detainee and ensuing protest at Harmondsworth is not the first time the immigration detention centre has come under scrutiny.
The centre was opened in 2001
Inspectors branded the centre unsafe for both staff and detainees in an official report published a year ago.
It warned of increasing disorder with an average of seven assaults a week.
A year after the centre opened in 2001, it was processing 12,000 asylum seekers a year - four times more than it was built to handle, inspectors found.
But in January of this year, the government said substantial improvements had been made.
The then Home Office minister Beverley Hughes said security at the west London centre had been stepped up and renovations were under way.
At the time she said: "The centre today is very different to when it was first inspected.
"I am confident that, when completed, the on-going works at the centre and the changes that have been made will address many of the concerns raised in the report."
In the report, chief inspector of prisons Anne Owers had found there was no means of securing the centre in the event of a riot and there had been no health and safety assessment of the risks to detainees.
And increasing levels of disorder at the centre included damage and escape attempts.
Some failed asylum seekers had resorted to starting fires, she added.
Ms Hughes said security had been stepped up, sprinklers installed and that capacity was to increase from 345 beds to 500 beds.
Harmondsworth holds people detained by the Immigration Service as overstayers, illegal entrants or failed asylum seekers prior to their removal from the country.
It also holds a smaller number of detainees whose cases have not yet been determined but who are thought to be at risk of absconding or whose identities have not been established.
In the September 2003 report, Ms Owers found there were reports of families, and a pregnant woman, held for hours in vans waiting for admission.
She heard of injuries to detainees during failed attempts to remove them and criticised procedures to prevent suicides.
The fast-track system used to deal with detainees at Harmondsworth has been branded "unlawful and unfair" by human rights lawyers.
But in March this year the Refugee Legal Centre, a publicly-funded body offering human rights protection for refugees and asylum seekers, lost a High Court challenge against the system.
The centre sought to extend the period allowed for cases to be considered.
The system began as a pilot in April last year.
Mr Blunkett described the speeding up of dealing with asylum claims as a "key focus" of his strategy to "tackle abuse of the asylum system".