Theresa May has refused to endorse Sajid Javid’s position on the death penalty despite admitting she knew about a letter sent to the US which paves the way for two members of the "Beatles" group of Isil terrorists to be sent to America.

The Telegraph revealed Britain had secretly abandoned its blanket opposition to the death penalty as part of a proposed deal which would involve captured jihadists Alexanda Kotey and Shafee El-Sheikh - who both held British citizenship - being prosecuted in US courts.

But Downing Street said the UK’s “long-standing position” was to “oppose the death penalty in all circumstances as a matter of principle” and failed to say whether Mrs May supported the decision.

Asked directly if Mrs May backed the move, the Prime Minister’s spokesman said: “Everybody agrees that these men should face justice through a criminal prosecution.”

Downing Street said the Prime Minister had been aware of the letter, sent to Jeff Sessions, the US attorney general, but would not say exactly when it was shared with her.

In the letter, Mr Javid said Britain will demand no "assurances" that the pair will not be executed in America.

"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," Mr Javid wrote, in the letter dated June 22 2018.