The International Brigades were often sacrificed by Republican commanders and the British had suffered heavy losses earlier in the year at Jarama and Brunete. One in five British volunteers would be killed during the war. Hilton’s first taste of combat came in the battle for the city of Teruel, in Aragon. This lasted much of the winter and Franco’s victory proved the turning point of the war.

Hilton’s most vivid memory of it was his surprise at the weather conditions, having assumed that Spain was always sunny. “I was always bloody cold,” he later recalled. Temperatures in the snow dropped to minus 20 C at night and more men died of exposure than wounds.

In March 1938 the Nationalists pressed home their advantage, aiming to reach the Mediterranean and divide the Republican South in two. The British contingent was forced to retreat and scattered on the banks of the Ebro. Surrounded and lost, Hilton and two comrades took refuge in a hut. When this came under fire, his companions were killed but Hilton escaped as he was outside at the time.

After swimming the broad River Ebro, he reached Barcelona, which he witnessed being bombed by Italian pilots. It was the first time that a major city had been attacked by modern aircraft and more than 1,000 civilians were killed. The scale of casualties was to influence Britain’s subsequent preparations for the Blitz.

Hungry and exhausted, Hilton convinced the captain of a ship headed for Britain, Lake Lugano, to let him come aboard and he worked his passage home.

Stanley Gordon Hilton was born at Newhaven, East Sussex, on December 31 1917. His early years were ones of poverty and his first memory was of being abandoned at a workhouse near Brighton. He was fostered for a time but later placed in a school where orphans were trained to be servants.

His nature never took readily to the imposition of authority and by the age of 16 he was sleeping rough. Then a friendly policewoman arranged for him to go to sea and he subsequently travelled the world on tramp steamers.