Currently Professor of Medicine and Head of the Division of Medicine at Imperial College London, Professor Walport will take up his position on 1 June.

He has been at Hammersmith Hospital since 1985 as Head of the Rheumatology Section in the Royal Postgraduate Medical School.

He was appointed Head of the Division of Medicine at Imperial College London in 1997. His clinical and research interests focus on immunology and the genetics of rheumatic diseases.

"I am absolutely delighted - the Wellcome Trust is a very special organisation," he said.

"Not only does it make huge contributions to biomedical research in the UK and internationally, it also plays an important role in supporting the medical humanities.

"I am looking forward enormously to leading the Trust during the coming years."

Commenting on the appointment, Sir Dominic Cadbury, Chairman of the Wellcome Trust, added: "Mike Dexter has made an invaluable contribution to the Trust over the past five years and the appointment of Mark Walport as his successor ensures that strong and effective leadership of our affairs will be continued.

"As a former Governor, his knowledge of Trust business combined with a proven track-record in science and management makes him the ideal candidate to take on the challenges which face such a large and diverse organisation."

Professor Walport won the Roche Rheumatology Prize in 1991 and the Graham Bull Prize in Clinical Science (Royal College of Physicians) in 1996.