He tried to join the post-monsoon 1939 Everest expedition led by Bill Tilman, but the attempt was called off. That year, he recorded the first of his many first ascents, that of Guan Nelda, 6303 metres (now called Chau Chau Kang Nilda) in the Spiti Himalaya. The ascent was remarkable for something which became a Roberts hallmark: he climbed without any other sahib for company, accompanied only by his Gurkhas. In this he was the true successor of the legendary Dr. A. M. Kellas who had climbed in the same fashion in Sikkim before 1914.