Paul studies the processes within clouds, on the microscopic scales which control the formation of rain and other precipitation, to the scales of organised weather systems. He makes use of field measurements, especially from the FAAM research aircraft, to develop new theoretical ideas about cloud processes and dynamics. As part of the Dynamics and Clouds research group at Leeds, he collaborates closely with those studying cloud physics and larger-scale weather systems. His group at the Met Office is using these results to develop the next generation of weather and climate prediction systems. Paul contributes to teaching of climate processes, and leads some activities on our fieldcourse programme.