Wilberforce (cat)
Wilberforce was just a kitten when he was adopted from a London branch of the RSPCA in 1973.  This was while Edward Heath was Prime Minister. He was appointed the Office Manager's cat, with a living allowance for his care. The black-and-white cat turned out to be a terrific mouser. The policeman on security duty at the front door of Number 10 had to ring the bell for Wilberforce whenever he wanted to come in.