The latest propaganda video by the Islamic State (ISIS) is thought to be a British man, Siddhartha Dhar .

The BBC reported that Mr Dhar was the focus of investigations into the video, which purports to show the killing of five men, ISIS said were spies.

Also known as Abu Rumaysah, Mr Dhar was arrested in 2014 on suspicion of encouraging terrorism but jumped bail.

The former businessman and father-of-four, from Walthamstow in East London, then made his way to Syria after being bailed.

In the latest video by the extremist group – which has not been independently verified, the masked man, who was holding a gun, mocked Prime Minister, David Cameron, for daring to “challenge the might” of the extremist group.

He went on to say: “We will continue to wage jihad, break borders and one day invade your land where we will rule by the Sharia.”

Mr Cameron said the video was “desperate stuff” from a group that was “losing territory”.