heavy harness pony breed derived from the cross of a Hackney horse and a Welsh pony, used almost entirely as a show pony. It has the conformation and high-stepping action of the Hackney horse. Hackney ponies are shown in classes determined by height, which varies from 11.2 to 14.1 hands (about 46 to 57 inches, or 117 to 145 centimetres). They are registered in the same studbook as the Hackney horse in both Great Britain and the U.S. See also Hackney.