Many authors have attempted to model the star formation history of the universe (eg Cole et al 1994, Pei and Fall 1995) or equivalently the evolution of the starburst galaxy population (eg Franceschini et al 1991, 1994, 1997, Blain and Longair 1993, Pearson and Rowan-Robinson 1996, Guiderdoni et al 1998, Dwek et al 1998, Blain et al 1999). Most of these studies explore a small range of models d...