Sir Thomas Leon Blundell, (born 7 July 1942) is a British biochemist, structural biologist, and science administrator. He was a member of the team of Dorothy Hodgkin that solved in 1969 the first structure of a protein hormone, insulin. Blundell has made contributions to the structural biology of polypeptide hormones, growth factors, receptor activation, signal transduction, and DNA double-strand break repair, subjects important in cancer, tuberculosis, and familial diseases. He has developed software for protein modelling and understanding the effects of mutations on protein function, leading to new approaches to structure-guided and Fragment-based lead discovery. In 1999 he co-founded the oncology company Astex Therapeutics, which has moved ten drugs into clinical trials. Blundell has played central roles in restructuring British research councils and, as President of the UK Science Council, in developing professionalism in the practice of science.