Manny Mercer

Mercer died on 26 September 1959 when a filly named Priddy Fair threw him before the start of the Red Deer Stakes at Ascot Racecourse. Mercer was fatally kicked in the head as he fell to the ground. Reporting on his death, The Age newspaper in Melbourne called Mercer "one of Britain's most brilliant race riders". In a article marking the fiftieth anniversary of his death, the Racing Post called him "one of its [racing's] brightest stars". Lindley, who was riding in the race before which he died, said "If he hadn't been killed he would have been one of the greats. I'd put him in the same class as Lester Piggott."

In 1954 Mercer won 88 races, including the 1954 2,000 Guineas Stakes on Darius, and finished second in the jockey standings to Doug Smith.

He captured the 1953 1,000 Guineas Stakes aboard Happy Laughter, trained by Jack Jarvis. Although he was second jockey to Bill Rickaby at Jarvis's yard, and Rickaby got to ride the stable's main hope, Tessa Gillian, Mercer had worked out how good Happy Laughter was, even though she'd been beaten in the Free Handicap. He told fellow jockey Jimmy Lindley that she was the best he'd ridden.

Mercer was a leading jockey throughout most of the 1950s, winning two British Classic Races. In 1952 he gained much media attention in the United States for his masterful ride on Wilwyn in winning the inaugural running of the Washington, D.C. International at Laurel Park Racecourse in Laurel, Maryland.

Emmanuel Lionel Mercer (15 November 1928 – 26 September 1959) was an English thoroughbred horse racing jockey. A brother of jockey Joe Mercer, he was married to Susan, the daughter of trainer Harry Wragg. Their daughters were Joanna and Carolyn, who married jockey Pat Eddery.