Isis video: Full transcript of 'A Message to David Cameron'

Security services are facing mounting questions over how a British jihadist believed to be the militant seen threatening the UK in Isis’ latest execution video was able to flee to Syria.

Authorities have not confirmed that the man is Siddhartha Dhar, who called himself Abu Rumaysah while touting his support for the so-called Islamic State last year.

Only the eyes of the militant were visible in the footage, which showed him wearing a black mask and military fatigues as he pointed a gun at the camera.

Here is the full transcript of Isis’ “message to David Cameron”:

This is a message to David Cameron. Oh slave of the White House, oh mule of the Jews. How strange it is that we find ourselves today hearing an insignificant leader like you challenge the might of the Islamic State. How strange it is that a leader of a small island threatens us with a handful of planes. One would have thought you would have learned the lessons of your pathetic master in Washington and his failed campaign against Islamic State.

It seems that you, just like your predecessors Blair and Brown, are just as arrogant and foolish. In fact David, you are more of an imbecile. Only an imbecile would dare to wage war against a land where the law of Allah reigns supreme. And where the people live under the justice and security of the Sharia.

Only an imbecile would dare to anger a people who love death the way that you love your life. Oh British Government, oh people of Britain - know that today your citizenship are under our feet. And that the Islamic State, our country, is here to stay. And we will continue to wage jihad, break borders and one day invade your land where we will rule by the Sharia.

But as for those of you who wish to continue fighting under the banner of Cameron on the minimum wage, we say to you, to ask yourself, do you really think your Government will care about you when you come into our hands? Or will they abandon you, as they have abandoned these spies, and those who came before them? Because you will lose this war, as you lost in Iraq and Afghanistan.

But this time when you lose, your children will pay for your deeds. And remember you as the fools who thought they could fight the Islamic State.

The jihadist then shot a prisoner kneeling in front of him in the head at point-black range before the four other Isis fighters flanking him did the same, murdering the alleged “spies”.

A young boy, now dubbed “Jihadi Junior”, was featured at the end of the footage in what appeared to be a warped trailer for a new execution video said to be “coming soon”.

He was identified by a man claiming to be his grandfather as Isa Dare, the son of British “jihadi bride” Grace Dare, who travelled to Syria in 2012.

The Prime Minister called the video “desperate” and said the latest threats showed Isis lashing out over recent territorial losses in Iraq and Syria.