Clifford made his debut of the
WDF World Cup in 1977 in an Irish team which contained, among others,
Jim McQuillan. Clifford lost to
Eric Bristow from England. Also in 1977, he progressed to the second round of the
World Masters, losing 3–0 to Louis van Iseghem from
Belgium. Clifford made one
BDO World Darts Championship appearance in 1978, losing 6–0 to
Rab Smith from
Scotland. Clifford left the BDO in 1978. ==World Championship results==