A er graduation, he joined the Law Faculty at the University of She eld, where he was a lecturer from 1976 to 1990, a Senior Lecturer from 1990 to 1993, a Reader from 1993 to 1995, and became Professor of Public Law in 1995.
Tar éis dó na céimeanna a bhaint amach, chuaigh sé isteach i nDáimh an Dlí in Ollscoil Sheffield, mar a raibh sé ina léachtóir ó 1976 go dtí 1990, ina Léachtóir Sinsearach ó 1990 go dtí 1993, ina Léitheoir ó 1993 go dtí 1995, agus ceapadh ina Ollamh le Dlí Poiblí é i 1995.