London: An NHS doctor from East London who was previously accused of kidnapping western journalists in Syria may hold the key to identifying the jihadist who beheaded James Foley, intelligence sources have disclosed.

Shajul Islam was arrested and charged with kidnapping a British journalist, John Cantlie, in 2012 but was later released after his trial collapsed when Mr Cantlie was unable to give evidence.

US journalist James Foley speaks at Northwestern University's Medill School of Journalism in 2011. Credit:Reuters

His brother Razul, 21, also travelled to Syria and is currently believed to be fighting with the Islamic State in Iraq and the Levant (ISIL), the terrorist group which murdered Mr Foley.

Razul Islam is understood to be on a list of British Jihadis whom the security services are comparing with the footage of Mr Foley's killer, a British man known as 'John' described as the leader of a British cell of jihadists known as 'The Beatles'.