Urquhart was conscripted into the British army in 1939, at the age of 19, and stationed at Fort Canning in Singapore. He was taken prisoner when the Japanese invaded the island in the Battle of Singapore, which lasted from December 1941 to February 1942. He was sent to work on the Burma Railway, built by the Empire of Japan to support its forces in the Burma campaign and referred to as 'Death Railway' because of the tens of thousands of forced labourers who died during its construction. While working on the railway Urquhart suffered malnutrition, cholera and torture at the hands of his captors.