Tom is Professor of paediatric neuropathology at the UCL GOS Institute of Child Health (ICH), and an honorary consultant and clinical lead/laboratory director of the department of histopathology at Great Ormond Street Hospital. He is an editor of the WHO Classification of CNS Tumours (6th Edition) and was an editor of the WHO Classification of Childhood Tumours (5th Edition). He is a member of the cIMPACT-NOW consortium. He is the editor-in-chief of the journal, Neuropathology and Applied Neurobiology, and was an editor of the 10th edition of Greenfield’s Neuropathology. He is the clinical lead of the pathology group of the Children’s Hospital Alliance.