Water flooded the hold and Urquhart was washed over the side. The sea was thick with burning oil from other sinkings in the convoy. More than 240 of his comrades died that night. There were terrible scenes as men fought for a piece of driftwood that would support them. Urquhart found a one-man raft. By the fifth day, he was badly burned and unable to see. His eyes had been seared by the strength of the sun.

He was picked up, barely conscious, by a Japanese whaling ship and dropped off at Hainan Island. There, he and other prisoners who had survived the sinkings were paraded naked through the village. In mid-September he was taken by stretcher and lowered into the hold of another “hellship”.

Again the convoy was attacked by submarines, but after an 11-day voyage they reached Japan. Urquhart was put to work in a coal mine at Omuta. By that time he could hardly stand and scarcely knew his own name.

Dr Mathieson, a Scot serving in the RAMC, persuaded the Japanese to move Urquhart to the camp hospital, where he worked as an orderly. The doctor’s courage, dedication and skill saved Urquhart’s life and that of many others.

His camp was 10 miles from Nagasaki, and when the atom bomb was dropped on the city, his shrunken frame was knocked sideways by the blast. For several days he and his comrades feared that the Japanese would massacre them to destroy the evidence of their atrocities, but on August 21 1945 the camp commander announced the end of the war and the British gradually took over.

The son of a teacher, Alistair Kynoch Urquhart was born on September 8 1919 at Newtonhill, Aberdeenshire. He went to school at Robert Gordon College, Aberdeen, where he won prizes for academic work and sports. His family fell on hard times and he left aged 14 to work for Lawson Turnbull, plumbers’ merchants and electrical wholesalers.