Security minister Ben Wallace said Britain was prepared to waive its long-standing objection to executions in the case of captured fighters, Alexanda Kotey and El Shafee Elsheikh.

The men are suspected of being two of four militants, dubbed "The Beatles" because of their English accents, who took part in the kidnap, torture and murder of Western hostages.

"In this instance, and after carefully considered advice, the government took the rare decision not to require assurances in this case," Wallace told the lower house of Parliament.

His statement followed a leaked letter published in the Daily Telegraph from British Home Secretary Sajid Javid.

The two suspects were captured in Syria in January by a U.S.-backed Syrian force, and Britain and the United States have been in discussions about how and where they should face justice.

According to the Telegraph, Javid wrote to U.S. Attorney General Jeff Sessions saying Britain was not intending to request that the two men be sent to the United Kingdom, saying a successful prosecution in the United States was more likely.

Furthermore, he said Britain would not insist on guarantees the men would not be executed.

"I am of the view that there are strong reasons for not requiring a death penalty assurance in this specific case, so no such assurances will be sought," the letter said.

"As you are aware, it is the long held position of the UK to seek death penalty assurances, and our decision in this case does not reflect a change in our policy on assistance in U.S. death penalty cases generally, nor the UK Government’s stance on the global abolition of the death penalty."

Earlier on Monday Prime Minister Theresa May's spokeswoman said Britain wanted the militants to be tried in the most appropriate jurisdiction.

"HAUNT THE GOVERNMENT"

The opposition Labour Party accused Javid of "secretly and unilaterally" abandoning Britain's opposition to the death penalty.

"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," said Labour's Shami Chakrabarti.

The government's stance also drew criticism from its own party.

Conservative lawmaker Dominic Grieve asked if there was a precedent for the government deviating from its normal policy and why it had not asked for an assurance from the U.S..

"Those are the two key questions and until they are answered I have to say ... this issue is going to continue to haunt the government," he said.

The most notorious of the four so called "Beatles" was Mohammed Emwazi, known as "Jihadi John", who is believed to have been killed in a U.S.-British missile strike in 2015.

He became a public face of Islamic State and appeared in videos showing the murders of U.S. journalists Steven Sotloff and James Foley, U.S. aid worker Abdul-Rahman Kassig, British aid workers David Haines and Alan Henning, Japanese journalist Kenji Goto and other hostages.

The mother of James Foley said she did not want the men to be executed if found guilty.

"I think that would just make them martyrs in their twisted ideology. I would like them held accountable by being sent to prison for the rest of their lives," Diane Foley told BBC radio.