John Morton Leiper, or more commonly known as Jack Leiper, was an English cricketer.
He was born in Woodford Green.
He was a left-handed batsman and a right-arm fast-medium bowler and wicket-keeper who played for Essex. Having originally played for Essex"s Second XI during the 1948 Minor Counties Championship, it was two years before Leiper made his first-class debut, against Gloucestershire in the 1950 County Championship. Leiper had a difficult debut, scoring 6 and 0 runs during the game.
He made his second and final first-class appearance less than a week later, against Somerset, in which, despite making a duck in the first innings, he scored a brilliant innings of 44 before being caught out by Maurice Tremlett, grandfather of current England Test cricketer Chris.
Leiper remained in the Essex tailend for the entirety of his short first-class career.