MI5 and MI6 have been piecing together intelligence and evidence from the horrific video footage to track down the identity of the Islamic State killer who has been dubbed “jihadi John”.
Ambassador Peter Westmacott told US news network CNN Britain is on the brink of establishing who he is.
Foreign Office and Home Office officials refused to comment on the claims.
Downing Street said the Government was ‘stepping up’ efforts to defeat IS terrorists and announced that Lieutenant General Sir Simon Mayall has been appointed security envoy to Iraq’s Kurdistan region.
Body armour, night vision goggles and other non-lethal equipment will be supplied to Kurdish forces over the next few days, a spokesman said.
“As the Government’s security envoy to Iraq’s Kurdistan region, General Mayall will support Kurdish and wider Iraqi efforts to counter ISIL and work with Iraq’s leaders as they establish a unity government,” he added.
But the Government is facing demands to take tougher action against British men going to Iraq and Syria to fight for IS.
In an article for the Mail on Sunday, former shadow home secretary David Davis wrote: “Since these young men are in effect swearing allegiance to a hostile state, they should all forfeit their British citizenship — not just those who are dual nationals..”