Williams was born in Bridgend in Wales and studied at the Hereford Cathedral School and St John's College, Oxford, where he read Modern History.
He turned from advertising to writing "whodunnits": he wrote 23 novels in all, most featuring Mark Treasure, graduate of Jesus College, Oxford[2] and vice-chairman of a merchant bank, and his successful actress wife Molly.
A second series of books featured Chief Inspector Merlin Parry of the South Wales Constabulary, together with Sergeant Gomer Lloyd.
His books were twice shortlisted for the Crime Writers' Association Gold Dagger award and he was elected as a member of the prestigious Detection Club in 1988.
[1] His ashes are interred in the churchyard of St Mary, Thorpe, Surrey - the nearest Anglo-Catholic parish church to his home, where he had been a Cantor and regular worshipper for many years.