Police have named the elderly man who died on board a cruise ship hit by a suspected outbreak of the norovirus. Roy Sillett, 74, a pensioner from Norwich, died on the board the vessel on Monday. Hundreds of passengers and crew on the Marco Polo, which is berthed in Invergordon, Easter Ross, in Scotland, have shown symptoms of the bug. Five people have been treated in hospital after falling ill on the ship while a sixth was airlifted to hospital after developing a medical condition unrelated to the suspected norovirus outbreak. Transocean Tours, the ship's operators, said the Mr Sillett suffered a fatal heart attack, and his death was unrelated to the bug. NHS Highland said Mr Sillett had serious underlying health problems and a post-mortem examination would be carried out to establish the exact cause of his death. About 380 people on board the ship are showing symptoms of the illness, NHS Highland said. The health board is awaiting the results of tests to confirm whether the bug is the norovirus.