Search for UK jihadi in Isis video to use voice and vein recognition software

Intelligence experts hunting the unknown British jihadi and a young child shown in a new Islamic murder video will use the same identification techniques successfully used to track down Mohammed Emwazi, who was killed in a targeted US drone strike in November.

Emwazi, also known as Jihadi John, took months to be publicly identified by the security services after he appeared behind a mask in a series of series of videos showing the execution of western hostages in 2014 and 2015.