David Cameron pictured on 3 October 2014
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Alan Henning: Cameron statement on UK hostage 'killing'

A video purporting to show UK hostage Alan Henning being beheaded has been released by Islamic State militants.

David Cameron has said Britain would do all it could "to hunt down these murderers and bring them to justice".

Volunteer Mr Henning was on his fourth aid mission to Syria when he was captured within minutes of arriving in the country last December.