Labour has called for a joint inquiry into the death of a woman at Yarl's Wood immigration detention centre, ahead of a post-mortem tomorrow morning.
Speaking at an urgent Commons debate in the wake of the death, Yvette Cooper said there had been worrying reports of poor health service provision and sexual assault at the Serco-run immigration detention centre in recent years.
She demanded a joint inquiry by the Prisons Inspectorate and the Borders Inspectorate of Yarl's Wood operations and Serco's contract, with the home secretary having to report back to the Commons.
Immigration minister James Brokenshire refused to comment on the case while it was under investigation, although he said increased counselling and pastoral support was being provided following the death.
"It's far too early to draw conclusions at this stage and to indulge in speculation would be distressing to the family and irresponsible given the issues involved," he said.
However, many Labour MPs are increasingly losing patience with Serco after a steady stream of damaging stories from Yarl's Wood, which deals mostly with women detainees awaiting deportation.
Unconfirmed reports said the woman had been complaining of chest pains for some time, but had only been offered paracetamol. There were also reports she had been crying for help before she died.
There is serious concern about the standard of medical care offered at detention centres, despite Home Office assurances that it is up to NHS standards.
An independent medical adviser described to Politics.co.uk how a group of women who has been tackled by guards at Yarl's Wood following a hunger strike protest did not have accurate nursing notes on their medical condition.
"The nursing notes said they had no injuries and were fine," she said.
"When I saw them they clearly had wrist bruises which they sustained in Yarl's Wood. There were bruises on their backs as well. They were very distressed."
Campaigners are particularly concerned about the presence of rape survivors at the centre, because of the evidence that the conditions of detention have a traumatic effect on their recovery.
"As soon as you go into that centre you're in an environment that recreates images for you," the medical adviser told Politics.co.uk.
"She'd been raped as part of her torture and she now had a guard coming in every night to check her room.
"She massively deteriorated. She cried the entire time I was there. She was just terrified, looking around constantly.
"She didn't trust anyone. She threatened to kill herself."
Seven Serco employees have been dismissed in the last few years for inappropriate conduct at Yarl's Wood.
A spokesperson for East of England Ambulance Trust said: "We were called at 8.17am [Sunday] morning to reports of a woman who had experienced a cardiac arrest. Paramedics tried to revive her but sadly she died at the scene."
The death comes as campaigners focus their efforts on the case of Yashika Bageerathi, a Mauritian student who was detained at the centre on March 19th.
The A-level student fled her home country in 2012 to escape a relative who had been abusive.
She had been due to be flown out yesterday, but Mauritius Air refused to do so after a robust public campaign.
A Home Office spokesperson said: "Sadly, we can confirm the death of a female detainee at Yarl's Wood on 30 March.
"It would not be appropriate to comment further as the death is subject to a police investigation. The Prisons and Probation Ombudsman has been informed in line with standard procedure."
A spokesperson for Serco, which runs the detention centre, said: "A 40-year old female resident at Yarl's Wood immigration removal centre collapsed on Sunday morning soon after getting up. She was immediately tended by medical staff from the centre and by paramedics from the NHS East of England Ambulance Service, but did not regain consciousness and sadly died soon after.
"Bedfordshire police and officials from the Coroner's Office attended the centre to examine the scene and begin an investigation. Serco is cooperating fully with the relevant authorities in their enquiries into this tragic event. The death is not being treated as suspicious at this time. Next of kin have been informed."