Peta[note 1] (born Manninagh KateDhu, c. October 1963 – 1980) was the chief mouser to the Cabinet Office, beginning her term in 1964 and retiring around 1976.

Peta served during the premierships of three prime ministers: Alec Douglas-Home, Harold Wilson and Edward Heath.

[4] After Peter III was euthanised in March 1964 following a liver infection,[5] the lieutenant governor of the Isle of Man, Ronald Garvey, suggested that a Manx cat be his replacement.

[14][21] Home Office staff were told not to feed her morsels of food, as, by February 1967, Peta had become "inordinately fat";[22] that same year, she was accused of fighting with Harold Wilson's Siamese cat, Nemo.

[23] When attempting to break up the fight, Mary Wilson was scratched on her arm by Nemo, contracting sepsis which caused her to miss a dinner with the Italian prime minister, Aldo Moro, being held that night.