A video purporting to show the beheading of British hostage Alan Henning has been released by Islamic State militants.

The Salford taxi driver was delivering aid to Syria in December when he was kidnapped then held hostage by IS.

IS had threatened to kill the 47-year-old in a video showing the killing of Briton David Haines last month.

The UK Foreign Office said it was trying to verify the video, and if true it was a “further disgusting murder”.

Prime Minister David Cameron said: "The brutal murder of Alan Henning by Isil [IS] shows how barbaric and repulsive these terrorists are…

“We will do all we can to hunt down these murdered and bring them to justice.”

He said his thoughts were with the family of Mr Henning, who had gone to Syria to “help people of all faiths in their hour of need”.

Mr Henning’s wife Barbara had this week appealed for his release, saying: “He is innocent.”

IS has previously released videos showing the apparent beheadings of two US journalists James Foley and Steven Sotloff, and British aid worker Mr Haines.

The video released on Friday is yet to be verified, but it appears to show Mr Henning kneeling beside a militant, dressed in black, in a desert setting.

The footage ends with an IS fighter threatening a man they identify as an American.