Cert 18 Stars 5

This shocking documentary highlights the full extent of the medieval barbarity ISIS has inflicted on the populace of the Syrian city of Raqqa since 2011.

Easily the most harrowing film of the year, it’s a fascinating exploration of how the written word has been supplanted by smartphones and the internet as vehicles for political change.

Four ordinary men risk their lives by secretly filming the public beheadings, crucifixions and executions, all of which we witness here in graphic detail.

And the dignity, courage and faith demonstrated by the keyboard warriors will haunt you long after the final credits.