Lamb joined the consular service in China in 1921 as a student interpreter in
Peking. He subsequently served as consul in
Szechwan and
Manchuria. In 1935, he was appointed consul at
Shanghai where he served until 1937 before he was transferred to Peking. In 1940, he was appointed superintending consul and assistant Chinese secretary at Shanghai. He and his wife were kept under house arrest at Shanghai by the Japanese from December 1941 to August 1942 before they were released in an exchange of diplomats. In 1943, Lamb spent two years at
Minneapolis–Saint Paul, before returning to China near the end of the
War as Chinese counsellor at the British Embassy at
Chungking. From 1947 to 1949, after the amalgamation of the Diplomatic and Consular services, he served as minister at
Nanking, and then from 1951 to 1953, after the establishment of the Communist regime and the People's Republic of China, as
chargé d'affaires at Peking where, according to
The Times "he was the eyes and ears of the West during the
Korean War. Nonetheless, it was a difficult time, with Anglo-Chinese relations at their worst for many years". A highlight of his tenure was leading the British delegation at the
Conference in Geneva in 1954 on Indo-China which coordinated the partition of
Vietnam into North and South agreed in the Geneva Accords. == Personal life and death ==