A British hostage has been killed during an attempted rescue operation involving UK special forces in Nigeria.

Chris McManus, who was working in the country as a building firm contractor, had been held by terrorists associated with Islamist extremist group Boko Haram since last May.

Details of exactly how Mr McManus died remain unclear amid reports of a firefight at the start of the rescue operation and claims in Nigeria that he had been killed in a crossfire.

But Prime Minister David Cameron said initial indications were that the contractor from north-west England and an Italian colleague were "murdered by their captors, before they could be rescued".