He joined the Hadley Centre in 1990 where he developed its regional climate modelling capability and has subsequently applied it in many innovative ways - developing a consistent GCM/RCM modelling system; for systematic domain-size experiments; to develop climate timescale simulations driven by numerical weather prediction analyses; to provide multi-decadal regional climate change projections; developing GCMs to provide high quality boundary conditions for RCMs; to provide ensemble detailed regional climate change Scenarios. He was a lead author of the regional climate information chapters of IPCC Assessment Reports Three (Chapter 10) and Four (Chapter 11). He led the development of the regional climate modelling system PRECIS and has worked with institutes across all continents in the fields of climate prediction and climate scenario development.