B was employed as a joiner from 1969 until 1970 by JF Finnegan Ltd. From 1970 until 1974, he worked for Sheffield City Council as an assessor. During this period of employment he was exposed to asbestos. When he returned to work for the council in 1975, he was regularly given medical examinations. In April 1991 he was told that he had some left basal pleural thickening. He was also told that he could claim against his employer for the increased risk of cancer.