Blue Peter (1936–1957) was a British bred Thoroughbred racehorse whose career was cut short by the outbreak of World War II. He won The Derby and was later a Leading broodmare sire in Great Britain & Ireland. Bred and owned by Lord Rosebery, his sire was the good racehorse, Fairway and his dam Fancy Free was by Stefan the Great, a son of The Tetrarch. Blue Peter was buried in the Mentmore estate.