William Harold Henry Siddons (17 September 19224 November 1963) was a British film and television actor, appearing in Genevieve, The Dam Busters, Appointment in London, They Who Dare, The Purple Plain, Quatermass and the Pit, A Night To Remember and The Wrong Arm of the Law. He served in Bomber Command during the Second World War as a flight engineer, latterly with 582 Squadron as the Flight Engineer Leader on its formation in April 1944 and was a descendant of Sarah Siddons. His decorations included the Distinguished Flying Cross, awarded in January 1944.
Born in Belfast, Northern Ireland, on 17 September 1922, he was found dead in his car on 4 November 1963 aged 41, apparently by suicide. He was buried in the parish churchyard of Little Gaddesden, Hertfordshire, with the motto Per ardua ad astra on his gravestone.