The DNA molecules within any organism's cells must not change for normal development.

However, DNA molecules are not always stable and can be damaged.

During his scientific career Tomas Lindahl demonstrated how certain proteins, repair enzymes, were able to remove and replace damaged parts of DNA.

These discoveries have significant impact in our understanding of cancer and ageing processes.

Tomas was director of the Clare Hall Laboratories for 1986 to 2005 and is now an Emeritus Group Leader at the Francis Crick Institute.