The four year old British boy dubbed 'Jihadi Junior' has been filmed detonating the bomb which kills four ISIS prisoners in the group's latest execution video, the Daily Mail reports.

Isa Dare, the son of Muslim convert Grace 'Khadija' Dare from south east London, pushes the button that blows up four alleged spies sitting in a white car behind him.

Standing triumphantly next to the charred remains of the car, his hand raised to the sky, the boy then yells: 'Allahu Akbar.'

It is the second time the young boy, who was brainwashed after his mother took him to Syria three years ago, has appeared in one of the extremists' propaganda videos.

His grandfather told of how the child begged him to save him just days before he was forced to appear in the first video last month.

In what was seen as a 'promotion' of this latest murderous release, Dare was made to declare: 'We are going to kill the kuffar [non-believers] over there' - before pointing to the men killed in today's video.

The video, which is believed to be shot in ISIS's de facto capital of Raqqa, was entitled: 'They are the enemy so be aware of them.'

Before they were killed, the senior ISIS commander standing next to the boy threatened British Prime Minister David Cameron for arming the terror group's enemies in Syria.

Young Dare was brainwashed by ISIS fanatics after his mother, 24, who had links to Lee Rigby's killer, brought him to the warzone.

Mr Dare said he had reported Grace to the police on three occasions before she left for Syria and told them 'she's behaving in a very funny way'. 

Grace Dare is believed to have been radicalised online, then began attending the Lewisham Islamic Centre, where Fusilier Rigby's murderers Michael Adebolajo and Michael Adebowale are reported to have worshipped.