The Prime Minister’s Choice. Wilberforce, a champion mouser, was cat-in-residence at Downing Street for four Prime Ministers: Edward Heath, Harold Wilson, James Callaghan and Margaret Thatcher. When he retired he was replaced by Humphrey, named after Humphrey Appleby of Yes Minister fame. Humphrey lived at No 10 with three Prime Ministers – Margaret Thatcher, John Major and Tony Blair – before retiring in 1997 under slightly mysterious circumstances shortly after the arrival of the Blairs. Almost as celebrated is Postman Pat’s black and white cat, Jess.