Douglas Sannachan (born 1962 in Glasgow) is a Scottish actor most widely known for playing Billy the window cleaner in Gregory's Girl. His famous line was "If I don't see you through the week, I'll see you through a window". He grew up in the Calton area of Glasgow and was a pupil at John Street Secondary School, Glasgow. When he was 16 years old he was the subject of a chapter of a book called The Year of the Child by Bel Mooney. He has also recorded his voice for radio The Bell and the Tree (Radio Clyde), Choke the Gaffer (Radio Scotland) and Short Plays for Radio (Radio 4).