John is a Professor of Soil Science at Lancaster University, specialising in soil erosion and the transport of contaminants in overland flow and holds degrees from Reading and Cranfield University. He was one of the developers of the European Soil Erosion model (EUROSEM), which is used for erosion prediction world-wide, and led the Landcare Group of the National Soil Resources Institute before coming to Lancaster in 2002. He is an associate editor of the European Journal of Soil Science, science secretary of the European Geophysical Union's Soil System Sciences Division. He has acted as an evaluator for Defra and the EC and has published over 80 research publications.

John leads a research group focusing on understanding the mobilisation and transport of contaminants in overland flow, includng the prediction of the risk of their transfer to surface waters, tracing their movement and developing mitigation strategies for their control. He also works on landscape scale transfers of carbon, and consults on the sustainable management of soil in temperate and semi-arid environments.

John is the leader of the Lancaster Environment Centre's Catchment and Aquatic Processes Research Theme and a member of the Centre for Sustainable Water Management.