Kammala jumla mai zuwa: Ya yi wasanni goma sha biyu a gasar zakarun duniya ta IAAF daga 1977 zuwa 1995. Da kansa, wasan kwaikwayonsa ya zo a
1983 IAAF Gasar Cin Kofin Duniya, inda ya kasance na bakwai a duka. Clarke ya kasance mai lambar azurfa sau uku a gasar (1982, 1987, 1989) kuma ya kuma lashe tagulla a 1992, yana raba girmamawa tare da Mike McLeod, Hugh Jones, Julian Goater, Steve Kenyon, Karl Harrison, Carl Thackery, Kevin Forster, Steve Binns, Tim Hutchings, Gary Staines, Richard Nerurkar, da Eamonn Martin, da sauransu.