Sylvia Dillane was chairman of the North Sea Boating Club. At the same time that the Slitheen had hidden a spaceship in the North Sea, she was killed by the Slitheen (assuming she existed in reality and not as an alias) and her skin was used as a disguise for one of them. This Slitheen was called to 10 Downing Street to join with the other Slitheen. When Mickey Smith launched a missile at Downing Street, the Slitheen was killed. (TV: World War Three)