Manhunt vow after naming of Jihadi John

British prime minister David Cameron vowed to use all means at his disposal to hunt down militants such as ‘Jihadi John’ after the killer was unmasked as a Kuwaiti-born computer programming graduate from London.

The black-clad militant brandishing a knife and speaking with an English accent was shown in videos released by Islamic State (IS) apparently decapitating hostages including Americans, Britons, and Syrians.

“When there are people anywhere in the world who commit appalling and heinous crimes against British citizens, we will do everything we can with the police, with the security services, with all that we have at our disposal to find these people and put them out of action,” Cameron said.

Cameron refused to go into the unmasking of ‘Jihadi John’ as British militant Mohammed Emwazi, aged 26, but said people should give their support to the security services.

Emwazi was known to security services, which had tried to recruit him, according to prisoners’ group Cage. The case has sparked debate about whether security services let him slip through their grasp to join IS in Syria.

Dressed entirely in black, a balaclava covering all but his eyes and the bridge of his nose, and a holster under his left arm, Jihadi John became a menacing symbol of Islamic State brutality and one of the world’s most wanted men.

He used videos to threaten the West, admonish its Arab allies, and taunt Cameron and US president Barack Obama before petrified hostages in orange jumpsuits.

Emwazi’s name was first disclosed by the Washington Post. The Sun and The Daily Mail published a picture of a schoolboy Emwazi smiling and sitting cross-legged in a photograph from the St Mary Magdalene Church of England primary school in Maida Vale, London.

Born in Kuwait, Emwazi came to Britain aged six and graduated with a computer programming degree from the University of Westminster before coming to the attention of Britain’s main domestic intelligence service, MI5, according to an account given by Asim Qureshi, research director of Cage, a group that campaigns for those detained on terrorism charges.

Emwazi, a fluent Arabic speaker, said MI5 had tried to recruit him and then prevented him from travelling abroad, forcing him to leave the country without telling his family, Qureshi told a news conference in London.

In a meeting with reporters, Qureshi cast Emwazi as a kind and thoughtful young man who faced harassment from MI5, which apparently suspected he wanted to join the Somali Islamist militant group al Shabaab. Qureshi called him a “beautiful man”.

The daughter of David Haines, a Scottish aid worker beheaded by IS, told ITV news

she would not rest until Emwazi received a “bullet between his eyes”.