He has published over 1500 peer-review papers on asthma, COPD and related topics with >150.000 citations and has edited over 50 books (h-index>200). He is also amongst the top 50 most highly cited researchers in the world and has been the most highly cited respiratory researcher in the world over the last 20 years. He was elected a Fellow of the Royal Society in 2007, the first respiratory researcher for over 150 years. He has been a member of the Scientific Committee of global guidelines on asthma (GINA) and COPD (GOLD). He also serves on the Editorial Board of over 30 journals and is currently Editor in Chief of Up-to-Date Pulmonary Diseases. He has given several prestigious lectures, including the Amberson Lecture at the American Thoracic Society, the Sadoul Lecture at the European Respiratory Society and the Croonian Lecture at the Royal College of Physicians. He has received honorary MD degrees from the Universities of Ferrara (Italy), Athens (Greece), Tampere (Finland) and Leuven (Belgium). He is an Emeritus NIHR Senior Investigator,a Master Fellow of the American College of Chest Physicians (Master FCCP) and a member of the Academia Europaea (MAE). He was President of the European Respiratory Society 2013/14. He co-founded an Imperial spin-out company RespiVert, which was acquired by Johnson & Johnson and has developed novel inhaled treatments for COPD and severe asthma.
His research is focused on cellular and molecular mechanisms of asthma and COPD, understanding and developing therapies and research into biomarkers for these diseases. He is involved in multidisciplinary translational research which integrates basic science with clinical studies, thereby providing novel insights into common airway diseases.He is currently working on accelerated lung ageing and cellular senescence as a mechanisms of COPD.