Brutal murders and a threat to conquer Rome: Analysing the latest Islamic State video

A new video from the so-called Islamic State, released tonight, marks an important and terrifying moment in the rapid expansion of the terrorist group.

Unlike previous IS videos, this one seems to have been filmed outside Syria and Iraq. 21 Egyptian Christians are apparently slaughtered on the shores of the Mediterranean Sea in Libya.

The proximity to Rome is mentioned by the executioner. Suddenly, four years after the death of Gaddafi, Libya has once again become a national security issue for Britain and other countries.

As always with such video postings from IS, this is not just an act of terror but of theatre too. The executioners wear black, their victims are dressed in orange jumpsuits: this gruesome production resembles previous IS video releases, using the same style of editing and bearing the same logo.

It suggests that the group’s Tripoli division is not some distant cousin of the group causing terror in the so-called caliphate.

Rather, Libya appears to have become an important new frontier for the war that IS is fighting - and an illustration of the coalition’s failure to contain the group.