After leaving school he travelled to India with the firm of Symons, Barlow and Co, eventually becoming a senior partner.

[1] During the First World War he served as an officer with the Bombay Light Horse.

At the outbreak of the Second World War he was the Consul to Basel, working in intelligence, but as Germany invaded France in 1940, he was driven by Richard Arnold-Baker, an officer in the Secret Intelligence Service (MI6), to the mouth of the Gironde where the Nariva took them back to London so that he could take over the Special Operations Executive or SOE.

[3] Nelson, despite the government's objections, urged the war ministry to allow the SOE to support resistance groups in Europe.

[1] He wore himself out establishing the organisation, and retired in 1942 due to ill health.