Aid worker Alan Henning has reportedly been beheaded by Islamic State terrorists.

A video apparently showing the beheading has been released on the internet.

The footage appears to show the 47-year-old aid worker, who was kidnapped last December in Syria by IS militants, kneeling beside a knifeman dressed in black in a desert setting.

The video, which apparently shows the killing of the former taxi driver - the second such murder of a UK hostage - was posted on YouTube by IS.

In it, a man dressed in black, waving a knife, issues threats to prime minister David Cameron and the British parliament.

The man has a London accent, and is said to sound like the same man speaking in the other recent beheading videos of James Foley and Steven Sotloff.

The Foreign and Commonwealth Office says the video has not yet been verified, but it was reportedly released in the same manner as the earlier Isis beheading videos.

A Foreign and Commonwealth Office spokesman said: “We are aware of the video and are working urgently to verify the contents. 

"If true, this is a further disgusting murder.  We are offering the family every support possible - they ask to be left alone at this time.”

Since news of Mr Henning's apparent death broke, there has been an outpouring of tributes to the aid worker, with many sharing the now ubiquitous picture of him holding a child and asking for him to be remembered this way.

Bolton South East MP Yasmin Qureshi was among those who took to Twitter to pay tribute to Mr Henning.

She tweeted: "Very disturbed to hear news of Alan Henning. Barbaric and senseless. Thoughts and prayers with his family at this time of tragic loss."

Steven Mariner paid tribute on The Bolton News' Facebook page.

He said: "RIP Alan Henning. So sad. A man who lived to do good for others died at the hands of a coward who doesn't even show his face. Thoughts with his friends and family."

Prime minister David Cameron, in a statement as he arrived back in the UK after visiting UK troops including those engaged in air strikes on IS in Iraq, said: "The brutal murder of Alan Henning by Isil shows just how barbaric and repulsive these terrorists are.

"My thoughts and prayers tonight are with Alan's wife Barbara, their children and all those who loved him.

"Alan had gone to Syria to help get aid to people of all faiths in their hour of need. The fact that he was taken hostage when trying to help others and now murdered demonstrates that there are no limits to the depravity of these Isil terrorists.

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

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