Hunt for identity of masked killer who beheaded journalist James Foley

UK intelligence agencies are seeking the identity of the masked man with an English accent who was filmed beheading US journalist James Foley in Syria.

Prime minister David Cameron yesterday abandoned his family holiday to return to Downing Street for talks with foreign secretary Philip Hammond and intelligence and military officers.

The apparent involvement of a British citizen follows his recent warnings that the UK must help to defeat Islamic State because of the security threat it poses to the UK.

US authorities yesterdayconfirmed the authenticity of the video, which shows Mr Foley in an orange jumpsuit, kneeling before his throat is cut. His severed head is shown dumped on his body before the killer warns another kidnapped journalist, Steven Sotloff, will be executed next.

Mr Foley’s mother, Diane, said: “We implore the kidnappers to spare the lives of the remaining hostages. Like Jim, they are innocents.”

The militant who appeared in video, who called himself John and is believed to be from London, was identified by one of his former hostages as the ringleader of three British jihadists thought to be the main guards of foreign nationals in Raqqa, a stronghold of Islamic State rebels

He has been identified as the main rebel negotiator during talks earlier this year to release 11 Islamic State hostages, who were eventually handed to Turkish officials after ransom demands were met.

Sources in Syria recognised him as a pointman for hostage negotiations in Raqqa where he is said to have held discussions with several families of jailed foreign nationals over the internet.

One former hostage, held for a year in Raqqa, said the Briton was intelligent, educated and a devout believer in radical Islamic teachings. The three UK-born militants were referred to as “the Beatles” by fellow hostages because of their nationality, the former captive added.

Security services in the UK and US were yesterday analysing the propaganda footage, with forensic phonetics experts among those thought to be involved in trying to identify the masked militant from his accent.

Prof Paul Kerswill, a linguistics expert at the University of York, said he believed the man spoke in “multicultural London English” most commonly found in the East End. “He probably has a foreign language background but it sounds like multicultural London English, which is people from all kinds of backgrounds who mix in the East End, a new kind of cockney,” he said.

Dr Claire Hardaker, a linguistics experts at Lancaster University, studied the clip and said the man’s vowels marked him out as likely from the south-east of England, but most likely from London. “We’re definitely looking at a British accent, from the south, and probably from London, Kent or Essex.”

Britain's security services have warned for months about the number of homegrown terrorists leaving cities across the UK to fight in Syria or Iraq, with an estimated 500 Britons joining up to 700 French and 500 Belgians on the front lines.

Prof Peter Neumann, director of the International Centre for the Study of Radicalisation, at King’s College London, said an English-speaking militant was chosen to front the video to cause maximum impact in the West.

He said: “It’s not significant that British fighters have been beheading and torturing because that’s been happening for a year and a half. The significant thing is that this was an American and was connected to a direct message that, ‘we are targeting you’.”

Mr Foley, who was from an Irish-American family in Rochester, New Hampshire, was kidnapped in November 2012 while working for Agence France-Presse and the Boston-based GlobalPost.

US president Barack Obama said "no just God" would sanction the brutal nature of his death and he insisted air strikes against Islamic State would continue to prevent it advancing further in Iraq. "We will be vigilant and we will be relentless. When people harm Americans, anywhere, we do what's necessary to see that justice is done," he said in Massachusetts.

Mr Cameron has nudged the UK’s response to Islamic State forward carefully, fearful that he could face another MPs’ revolt against Middle East military action – as he did last year over Syria.

Last night, he ruled out deploying British army soldiers on the ground, although SAS forces are understood to be operating alongside the Kurds.

He said the Kurds would get “the arms they need” to fight Islamic State, but added: “We’re not going to put combat troops, combat boots on the ground.”

– (Additional reporting: The Guardian)