On the grandest stage in the biggest competition of them all, Collis became King for a day. June 1979. West Indies versus England in the final of the World Cup and his team were in trouble at 99 for four when he joined Viv Richards. Never before or since has such an occasion seen such an explosive, exotic totally instinctive display of batting. Never, for certain has Richards ,in royal form himself, been outshone quite so much. King made 86 from 66 balls, taking merciless toll from a weak England attack, and adding 139 with Richards in just 21 overs to put the match quite beyond England's grasp. He was never able to rise to the occasion in such a manner again. If he gave the ball a crack then it in no way equalled that which he gave life in general. His career was checked by his decision to join World Series Cricket and then effectively ended when he toured South Africa with the rebel West Indies side in 1982-83. He played a few more seasons for Natal in the Currie Cup afterwards, before retiring to England.

Mike Selvey