British PM confirms 'brutal murder' of Alan Henning by IS

British Prime Minister David Cameron has confirmed the "brutal murder" of aid worker Alan Henning by the Islamic State group and vowed to bring his killers to justice.

"The brutal murder of Alan Henning by ISIL (another term for IS jihadists) shows just how barbaric and repulsive these terrorists are," Cameron said in a statement released by his Downing Street office.

"We will do all we can to hunt down these murderers and bring them to justice."

A video which emerged yesterday shows Henning on his knees against a desert backdrop and wearing an orange prison-style outfit, with a masked militant standing over him wielding a combat knife before the video cut to his beheading.

Henning, a 47-year-old from Manchester in northwest England who volunteered to help drive an aid convoy to Syria for Muslim charity Aid4Syria, was kidnapped 10 months ago.

Cameron said the fact Henning was captured and killed while trying to help others "demonstrates that there are no limits to the depravity of these ISIL terrorists."

He added that his "thoughts and prayers" were with Henning's wife Barbara, their children and friends.