Absolute scum of the earth, these people are. I also saw a video with them executing swathes of captured combatants (well, they claim they were combatants) by making them all lie down and just walking along shooting them in the head and body with automatic weapons. They're then shown leading others one by one to a waterside, shooting them point blank in the skull, then pushing them into the water.
I honestly hope that that piece of **** doing the beheading videos attempts to return to the UK when all of this inevitably goes south for IS, is caught and imprisoned, and quite literally ripped to pieces in there.
In reality, though, he'll probably just get the easy escape of a bullet to the brain or bombed to death.