DAVID Cameron has spoken out in defence of the intelligence and security agencies after they were criticised in the wake of Jihadi John being identified as a London university graduate.

The Prime Minister said it was "reprehensible" to claim that they were partly to blame for him turning to violence due to alleged harassment and interrogation.

Speaking after the militant - who killed Scot David Haines and a number of other hostages - was revealed as Kuwait-born Mohammed Emwazi, Mr Cameron said his "number one priority" was to ensure those responsible for crimes against British citizens were hunted down and "put out of action".

Meanwhile, the north-west London secondary school attended by Emwazi said it was "shocked and sickened" that the former pupil has been unmasked as an Islamic State terrorist.

In a statement released by Westminster Council, a spokeswoman for Quintin Kynaston Community Academy said: "There has been much press speculation in recent days concerning allegations about a former student Mohammed Emwazi, who left almost nine years ago.

"If the allegations are true we are all extremely shocked and sickened by the news.

"All members of staff at QK work very hard to support the education and well-being of our students and protect them from harm.

"In this respect, QK has been extremely proactive in working with the Government's Prevent strategy for a period of time and will continue to be so for the foreseeable future."

Westminster University also said it was carrying out an investigation into how a photograph showing Emwazi as a student there was released to the media.

At a press conference in London earlier this week, Emwazi's former confidante, the research director of advocacy Cage Asim Qureshi, described him as "extremely kind" and "extremely gentle".

Mr Qureshi said Emwazi's family was "in utter shock" and unable to accept his role as executioner for the Islamic State group which has seized control of large swathes of Iraq and Syria.

Cage also hit out at MI5 for "systematically" harassing young Muslims.

Mr Cameron declined to comment directly on Emwazi, but said it was important for Britain to "get behind" the security services.

He said: "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 security services, with all that we have at our disposal, to find these people and put them out of action.

"That is the number one priority for me.

"All of the time, (the security services) are having to make incredibly difficult judgments and I think basically they make very good judgments on our behalf, and I think whilst we are in the middle of this vast effort to make sure British citizens are safe, the most important thing is to get behind them."

Bethany Haines, the daughter of Scottish aid worker Mr Haines, who was killed by the Islamic State, has said families would only feel closure "once there's a bullet between (Emwazi's) eyes".

Asked whether Mr Cameron shared the same view, a Downing Street spokeswoman replied: "The Prime Minister wants to see the murderers brought to justice."

Scotland Yard has refused to confirm reports of Emwazi's identity.