Humphrey - As a one-year-old stray, Humphrey served as Chief Mouser to the Cabinet Office at 10 Downing Street under the premierships of Margaret Thatcher, john Major, and Tony Blair. He was frequently referred to in jest by the press as an actual employ at Number 10. He retired 6 months after the Blairs moved in to Downing Street.
Apparently, this is not a Photoshop mashup of two kitties. This, a Janus cat, was named so because it was born with two faces. Frankie and Louie is a Guinness World Record holder for "Longest Surviving Janus Cat.