(en) Alex. C. McKay, The Establishment of the British Trade Agencies in Tibet: A Survey, in Journal of the Royal Asiatic Society (1992), Third Series, 2, pp. 399-421 : « After 1936 a mission was stationed in Lhasa. The last British official in Lhasa, Hugh Richardson, departed in 1950 following the Chinese invasion of Tibet ».
(en) Bureau du Tibet, "For Tibet the nightmare of foreign occupation had begun," Robert Ford, 6 juillet 2008 : « Mr. Ford joined the British Mission in Lhasa in 1945 as a radio officer. The same year he was transferred to Gangtok (Sikkim), where he worked for British-India relations with Tibet. In 1947 when India became independent, he returned to Lhasa and became the first foreigner to be given an official Tibetan rank after his appointment by the Government of Tibet. »
(en) Heather Spence, British Policy and the 'development' of Tibet 1912-1933, Doctor of Philosophy thesis, Department of History and Politics, Faculty of Arts, University of Wollingong [Australia], 1993, x + 362 p. : « The Nanking government saw in the Thirteenth Dalai Lama's death the opportunity to send a 'condolence' mission to Lhasa. When the mission returned to China, two liaison officers with a wireless transmitter remained at Lhasa. In a counter-move, a rival British Mission was quickly established by Hugh Richardson ».
