After graduating from the University of Cape Town in 1973 he did a D.Phil in Oxford, in transplant immunology. He trained in nephrology at the Hammersmith Hospital, Royal Postgraduate Medical School, where he was part of the team that first investigated the effect of recombinant human erythropoietin in uraemic man. He has been a consultant nephrologist in Oxford since 1988 and was the Clinical Director from 1995-2009. He was a Fellow of Jesus College from 2005- 2015. He was made an Associate Professor of Medicine at the University of Oxford in 2015 and received a teaching award for his service as Principal Examiner in Medicine.. He retired from full-time work in 2016. He was the Secretary and later Clinical Vice President of the UK national society, The Renal Association. He was a Censor of the Royal College of Physicians and the Osler Orator in 2005. He is an Editor of the Oxford Textbook of Clinical Nephrology now in its 4th Edition. His research interests include: renal anaemia myeloma kidney and polycystic kidney disease. More recently he, with Professor Richard Glassock challenged the original CKD construct and later served on the KDIGO working group which revised it.