David Cameron has condemned a "despicable and barbaric" Islamic State video that appears to show the murder of US journalist Steven Sotloff.
The Prime Minister will chair a meeting of the Government's Cobra emergency committee tomorrow morning in response to the latest video.
I've been told at the Nato summit that the intelligence services know exactly who 'Jihadi John' is - or at least are 99.9% certain.
The British aid worker being held by Islamic State is David Haines, a 44-year-old father-of-two from Perth, Scotland.
In a video statement which claims to record his final words US hostage and journalist Steven Sotloff blames US foreign policy for his death.