David Cawthorne Haines Beheaded

British Prime Minister David Cameron has responded on Twitter:

The murder of David Haines is an act of pure evil. My heart goes out to his family who have shown extraordinary courage and fortitude.
— David Cameron (@David_Cameron) September 13, 2014

We will do everything in our power to hunt down these murderers and ensure they face justice, however long it takes.
— David Cameron (@David_Cameron) September 13, 2014

And at Mirror UK, "David Haines 'beheading': Latest updates after ISIS video claiming to show execution of British hostage."

More at Telegraph UK, "Foreign Office working urgently to verify video showing British hostage David Haines 'beheading' by Isil terrorists." And BuzzFeed, "New ISIS Video Purports To Show Execution Of British Citizen."

Added: At Bare Naked Islam, "Islamic State (ISIS) claims to have beheaded British hostage, David Haines, and is threatening to behead another Briton, Alan Henning."