The material was uploaded onto the accounts of two men from London, thought to be fighting in Islamist rebel groups that have some links to Jahbat al Nusra.
Jahbat al Nusra is the only jihadi outfit operating on the ground in Syria that is explicitly endorsed by al Qaeda’s global leader.
It shows a prisoner, apparently from the Free Syrian Army, being beaten for insulting Allah.
The FSA prisoner is heard shouting his innocence as he is bound to a car tyre and beaten across the legs with what appears to be a metal baton.
As he writhes around on the floor, one of the men stamps on his head.
As the beating continues he begs them not to kill him.