Writing in The Times on Friday, signatories including Lord Alton of Liverpool (pictured below) referred to claims the Government decided not to grant Asia Bibi asylum over fears of reprisals from hard-line Islamists.
They said: "We are deeply concerned by reports that Theresa May is refusing asylum to Asia Bibi, who remains in mortal danger in Pakistan."
Asked by a fellow Conservative MP to "put the record straight" regarding the claims, the Prime Minister told Zac Goldsmith on Wednesday he "shouldn't necessarily believe everything he reads in the newspapers".
But Lord Alton, along with Baroness Cox (pictured at end of article) and Lord Forsyth of Drumlean warned ministers against "capitulating to the threats of lynch mobs".
They continued: "Britain's position indicates a serious betrayal of our time-honoured commitment to offer asylum to those in need.
"It also undermines our belief in justice, human rights, the rule of law and religious freedom, and risks us falling foul of, and succumbing to, blackmail".
Ms Bibi and her family became the subjects of death threats following a decision by Supreme Court in Islamabad to acquit her of blasphemy last month.
The mother-of-five always denied claims she insulted the Islamic prophet Mohammad but hard-line Islamists have been calling for her public execution.
She is currently in hiding. The family hopes to live Pakistan and flee to a country in the West.
Speaking during Prime Minister's Question on Wednesday, Theresa May said Ms Bibi's safety was "the absolute prime concern".
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