Six offshore workers were killed and another missing feared dead after a helicopter belonging to an Aberdeen-based firm ditched into the Irish Sea. The aircraft, carrying five Centrica employees and two crew, ditched into freezing water 25 miles off the between the Isle of Man and Morecambe Bay on the Lancashire coast. The Aerospatiale SA-365N Dauphin 2, operated by CHC Scotia Ltd, ditched close to a gas drilling plaftorm on its last journey ferrying workers back to shore. The search continued last night as hope faded for the one remaining crew. Two RAF helicopters - one from RAF Valley and one from RAF Leconfield - as well as RNLI lifeboats from Fleetwood and Barrow were also helping with the search as were several support vessels.