Hugh John Forster Cairns FRS[3] (21 November 1922 – 12 November 2018) was a British physician and molecular biologist who made significant contributions to molecular genetics, cancer research, and public health.

Cairns took a sabbatical to research at the Cold Spring Harbor Laboratory between 1960 and 1961, and returned there to serve as the director from 1963 to 1968.

He remained a staff member at Cold Spring Harbor until 1972, when he was appointed head of the Mill Hill Laboratory of the Imperial Cancer Research Fund.

After leaving Mill Hill in 1980, he took up a professorship at the Harvard School of Public Health.

Subsequently, it was found that there were in fact two moving forks, traveling simultaneously in opposite directions around the chromosome.