He told me that Francis Crick and Jim Watson had solved the structure of DNA, so we decided to go across to Cambridge to see it. This was in April of 1953.

In my second year, after moving to the Medical School, I began the courses of Anatomy and Physiology. I had begun to see that I was interested in cells and their functions.

During this period, I became interested in how the new techniques of cloning and sequencing DNA could influence the study of genetics and I was an early and active proponent of the Human Genome Sequencing Project.

The moment I saw the model and heard about the complementing base pairs I realized that it was the key to understanding all the problems in biology we had found intractable - it was the birth of molecular biology.

I lived at home and I cycled every morning to the railway station to travel by train to Johannesburg followed by a walk to the University, carrying sandwiches for my lunch and returning in the evening the same way.

There was still food rationing in England and life was difficult all through my 2 year stay in Oxford.