Third British hostage appears in shocking new ISIS propaganda video urging UK to negotiate with terror group

British journalist John Cantlie calls himself a prisoner of the Islamic StateHis voice is clear and calm as he speaks in slickly-edited propaganda video.Appearing to read from a script, he says that he arrived in Syria in 2012.Mr Cantlie promises to reveal 'the truth' in a series of 'programmes' .He was previously kidnapped by Islamic extremists in Syria in July 2012.The journalist and his colleague escaped with help from Free Syrian Army. He is the third Briton named as a hostage of the Islamic State