The identity of a Tower Hamlets-born terrorist who said Muslims in the borough should “cut the necks of disbelievers” in a jihadi recruitment video has been revealed.

Taufail Ahmed, praised as a “martyr” in the video from Somali terror group al-Shabab, was a Bangladeshi-Briton who went to Stepney Green School, according to a BBC investigation.

Muslims who knew him in London said he became involved in gangs as a teenager, but became more pious and fanatical in his early 20s.

They said he was influenced by hardline Islamic preachers like Abdullah e-Faisal and al-Qaeda recruiter Anwar al-Awlaki.

Al-Shabab say Ahmed was killed in a raid by British and American forces in November 2012.

The government has declined to comment on the claim.

Robin Simcox, terrorism expert at think-tank the Henry Jackson Society, said: “The security services know there is a pipeline that takes fighters from Britain to join with al-Shabab in Mogadishu [Somalia’s capital].”

Mr Simcox said it was less clear whether there are al-Shabab recruiters operating in London, but the work of preachers like al-Awlaki, who was killed in a drone strike in 2011, is available and very effective.

Al-Shabab claimed responsibility for the attack on Westgate shopping centre in Kenya last month that killed 67 people.

If you have any information about Taufail Ahmed, call 020 8477 3886.