Theresa May has failed to reply to a letter from over 40 MPs and peers calling on her to show mercy to an asylum seeker who is expected to die soon unless he is released from detention.
Isa Muazu has not eaten anything in nearly 90 days, but the Home Office has declared him 'fit to fly' and is pushing for him to be deported on a scheduled flight.
Although there has been little press attention on the case, the home secretary is coming under growing political pressure to soften her stance.
Politics.co.uk can reveal that deputy Lib Dem leader Simon Hughes is asking Nick Clegg to step in and talk the home secretary out of her hardline position, in a move which could worsen already delicate relations between the deputy prime minister and the home secretary.
Liberal Democrat MP Julian Huppert meanwhile tabled an urgent question for the Commons on Monday, although the matter will probably be considered sub-judice until after a court hearing also tabled for that day.
"In any civilised country to allow people to starve to death is something we shouldn't really contemplate," Lord Roberts of Llandudno, who organised the open letter, told Politics.co.uk.
"We are hoping the appeal on Monday succeeds. It would be a lifesaver. Otherwise a prolonged hunger strike could only end in death itself.
"The UK is way beyond the time we'd allow someone to starve to death of hunger."
Critics say the row is similar to that over Irish hunger striker Bobby Sands, whose death on hunger strike in 1981 caused worldwide protests against the British government.
Muazu claims he will be killed by Islamic extremist group Boko Haram if he is returned to Nigeria. He says the group has already executed members of his family.
He began a hunger strike in September in protest at his continued detention.
The letter to May, which has been signed by Lib Dem peer Baroness Shirley Williams, Respect MP George Galloway, Green MP Caroline Lucas, Labour MP John McDonnell and others, demands that Muazu is immediately released on bail so he can be cared for in a hospital.
"We are writing in relation to the case of Mr. Isa Muazu, a Nigerian national, who has been on a hunger strike for almost ninety days at Harmondsworth Detention Centre," it reads.
"As he is unfit for detention, we ask that you immediately release him on bail so that he may be admitted to hospital and receive the urgent medical treatment he clearly requires.
"We understand that he is now so near to death that there may not be enough time to appeal his case.
"We hope that you will reconsider releasing him from detention as a matter of urgency."
The letter was sent three days ago, but there has been no response from the home secretary.
Speaking to Politics.co.uk, a case worker for the Nigerian national said he was now so weak he had lost his sight and could not stand up.
Nevertheless, the Home Office told the court yesterday that its doctors had said he was 'fit to fly' and could be deported to Nigeria.
Campaigners are calling for supporters to back an online appeal for the Nigerian national.
Protests are planned for outside of Harmondsworth detention centre this weekend and on Monday.