Islamic State: David Cameron defends security services after media unmask 'Jihadi John'
British prime minister David Cameron has defended security services and vowed to hunt down "Jihadi John", the Islamic State (IS) group militant who has appeared on video beheading hostages and has been named as a London graduate.
Former computer programmer Mohammed Emwazi has been named as the IS group militant believed to be responsible for murdering at least five Westerners including United States journalist James Foley.
"When there are people anywhere in the world who commit appalling and heinous crimes against British citizens, we will everything we can to find these people and put them out of action," Mr Cameron said.
Mr Cameron was asked to explain why the Kuwaiti-born British citizen was able to travel to Syria to join IS in about 2012, despite being known to authorities.
He urged the public to back the security services.
"All I can say, is even in the last few months, their dedication and work has saved us from plots on the streets of the United Kingdom that could have done immense damage and so I think it is a moment to stand up and thank them for the work they do on our behalf," he said.
In an interview with the BBC Sir John Sawers, a former head of MI6, rejected suggestions it was an oversight not to have him under stricter controls.
"There are probably several thousand of these individuals of concern and the numbers are rising as more people go to Syria and Iraq and are radicalised out there," he said.
"And no-one's talking about rounding up all these people or keeping 100 per cent coverage of them.
"There's just not the resources for that and it would be contrary to our principles of human rights to do that."
The widow of aid worker David Haines, one of Emwazi's British victims, said she was shaken by news that the masked killer had been identified.
"It's just difficult to digest. It's difficult to accept that such a young person, educated person could turn into something so inhuman," she said.
She said she did not want to see her husband's killer murdered.
"For him it would be easy just to be killed and it's over. I want him to try to realise, through the fair trial, what he has done to our family," she said.
As well as Haines and Foley, Emwazi is also believed to have killed US journalist Steven Sotloff, British aid worker Alan Henning and US aid worker Abdul-Rahman Kassig.
At the house of Emwazi's family in west London nobody is home. Neighbours said they had not seen the family for several days.
Emwazi's name was first disclosed by the Washington Post, citing unidentified former associates, but two US government sources confirmed investigators believed Jihadi John was Emwazi.
The Washington Post and BBC said Emwazi, in his mid-20s, was born in Kuwait but grew up in a middle-class family in west London.
According to reports, Emwazi moved to Britain at the age of six.
