The Government has defended a decision not to seek assurances from Washington that two Britons suspected of fighting for Islamic State would not face execution if extradited to the US to face terror charges.

Downing Street said Theresa May backed the decision by Home Secretary Sajid Javid not to seek “death penalty assurances” as the case of two suspected members of IS’s so-called “Beatles” cell sparked uproar in Westminster.

MPs on all sides accused Mr Javid of breaching the UK’s long-standing opposition to the death penalty, while the Government’s former reviewer of anti-terror legislation Lord Carlile branded the move “extraordinary”.

It emerged on Monday night that Boris Johnson backed Mr Javid’s decision in the case of Alexanda Kotey and El Shafee Elsheikh while still foreign secretary despite some reservations.

The Daily Telegraph reported an internal document which said he thought it could damage future attempts to dissuade the use of the death penalty but “agrees that the benefits outweigh the risks in this instance”.

Amnesty International said Mr Javid was “leaving the door wide open to charges of hypocrisy and double standards” by failing to seek “cast-iron assurances” from the US that the two men will not be executed.

Home Office minister Ben Wallace was summoned to answer questions from alarmed MPs in the Commons, where he insisted that there had been no other cases of the requirement being waived since he took on the security brief in 2016.

Asked whether the Prime Minister approved of Mr Javid’s position, set out in a letter to US attorney general Jeff Sessions obtained by The Daily Telegraph, a Downing Street spokeswoman initially said only that Mrs May was “made aware” of it, adding that the Government opposes the death penalty “in all circumstances as a matter of principle”.

Syria conflict
Alexanda Kotey, one of two Britons suspected of having been part of the Islamic State extremist group dubbed ‘The Beatles’ who were captured by Kurdish militia fighters in January (ITV News/PA)

But Number 10 later shifted its line, telling reporters that Mrs May “supports” the Home Secretary’s handling of the case and hopes it will end with the two men remaining in prison for the rest of their lives.

“The ultimate aim for all of us in our discussions with the US is to make sure that these men face the rest of their lives in prison. That is also what the victims’ families want,” said the Downing Street spokeswoman.

“In this instance, after careful and considered advice, the Government took the decision not to seek assurances. That was deemed by ministers to be appropriate.

“The Prime Minister was aware of these plans and supports the way that these are being handled.”

Kotey and Elsheikh are said to have been members of a brutal four-man cell of IS executioners in Syria and Iraq, responsible for killing a series of high-profile Western captives, including British aid workers David Haines and Alan Henning and US journalists James Foley and Steven Sotloff.

Nicknamed after the 1960s band because of their British accents, the cell is also believed to have included Mohammed Emwazi – known as “Jihadi John” – who was killed in a US air strike in 2015, and Aine Davis, who has been jailed in Turkey.

Kotey and Elsheikh, who are understood to have been stripped of their British citizenship, were captured in January, sparking a row over whether they should be returned to the UK for trial or face justice in another jurisdiction.

The letter sparked alarm in Westminster, with shadow attorney general Baroness Chakrabarti saying that Mr Javid appeared to have “secretly and unilaterally abandoned Britain’s opposition to the death penalty”.

Jihadi John named
Screen grab from footage issued by Islamic State militants of the British extremist Mohammed Emwazi, known by the nickname ‘Jihadi John’ (PA)

She warned: “By doing so he is not just playing with the lives of these particular terrorists but those of other Britons – including potentially innocent ones – all over the world.”

Lord Carlile described the move as “a dramatic change of policy by a minister, secretly, without any discussion in Parliament”.

Liberal Democrat home affairs spokesman Sir Ed Davey said: “By refusing to stand up to Donald Trump’s administration on this issue, Sajid Javid has abdicated his responsibility to uphold fundamental human rights.”

David Isaac, chairman of the Equality and Human Rights Commission, said: “Opposing the death penalty is one of the fundamental principles that underpins our country’s commitment to human rights. There is no conflict between these values and ensuring that justice is served.”

Mr Wallace assured the Commons that ministers have complied with the European Convention on Human Rights and due process.

But he was heckled by opposition MPs as he said it would be “bizarre and not justice to the victims” if the authorities “simply let them free to roam around the United Kingdom” because of concerns about sharing evidence with the US.

Tory former attorney general Dominic Grieve said the decision represented a “major departure from normal policy”, adding: “Those are the key questions and until they’re answered I have to say to him this issue is going to continue to haunt the Government.”