Lengkepan kalimah di handap ieu: Manéhna nyieun dua belas appearances di IAAF World Cross Country Championships ti 1977 nepi ka 1995. Individually, pagelaran-Na sumping di
1983 IAAF World Cross Country Championships, di mana anjeunna nempatkeun katujuh sacara umum. Clarke meunang medali pérak tilu kali dina kompetisi (1982, 1987, 1989) sarta ogé meunang perunggu tim dina 1992, ngabagi kahormatan jeung Mike McLeod, Hugh Jones, Julian Goater, Steve Kenyon, Karl Harrison, Carl Thackery, Kevin Forster, Steve Binns, Tim Hutchings, Gary Staines, Richard Nerurkar, jeung Eamonn Martin, antara séjén.