The Islamic State group threatened Britain in an Internet video Sunday showing the killing of five “spies” it said worked with the international coalition fighting ISIS in Iraq and Syria, reported Inquirer.

The footage on Sunday bears the markings of the IS media wing, and shows five men ‘confessing’ to filming and photographing sites in exchange for money within Raqqa, the capital of the Islamic State group’s self-declared caliphate.

It could not be independently verified.

The men, speaking Arabic, are introduced as ‘the enemy’ and ‘apostates.’ Later they kneel lined up in orange jumpsuits in the desert, where they are shot in the head by masked executioners.

Before the shooting, a masked man with a British accent mocks British Prime Minister David Cameron, calls the men ‘spies,’ and says IS will one day invade Britain and impose their version of Islamic law.

According to BelfastTelegraph, the video bears similarities to those which featured the British jihadist known as Jihadi John. The killer, real name Mohammed Emwazi, appeared in videos showing the execution of Britons David Haines and Alan Henning, plus those of US journalists James Foley and Steven Sotloff. Emwazi was killed in a US drone strike in Syria in November.

The 10-minute recording also features a small boy.

It comes days after Mr Cameron promised to crack down on IS sympathisers, stressing in a New Year’s message that all Britons should have “loyalty” to their country.

Pointing a handgun, the masked jihadi addresses Mr Cameron, saying: “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 the Islamic State.

“But it seems like you, just like your predecessors Blair and Brown are just as arrogant and foolish. In fact David, you (waves handgun) 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 you love your life.”