President of IUBS 1994-97, an Hon. President of the International Mycological Association, and currently an Honorary Research Associate at the Royal Botanic Gardens Kew and a Scientific Associate at The Natural History Museum London. He was the last Director of the International Mycological Institute, and subsequently a Research Professor in the Universidad Complutense de Madrid.
He has research interests in diverse aspects of the taxonomy, nomenclature, and diversity of fungi (including lichens) and their applications, and is Editor-in-Chief of both Biodiversity and Conservation and IMA Fungus. His medals and awards include appointment as CBE (Commander of the British Empire) by HM Queen ElizabethII.