In 1981, the one horse whose legend stretches beyond racing, streaked to a record 10-length success. Shergar may not have been the best Derby winner ever, but the manner in which he won, the fact he had the choirboy-featured Walter Swinburn on his back and, tragically, his kidnapping by the IRA during his first year at stud, made him the most famous Flat racehorse of modern time.