A British Secret Intelligence Service officer in World War I, Captain Best joined the Z Organization in The Hague, where he was a well-known member of the British expatriate community in the late 1930s, running a business importing the very popular Humber bicycles. Supposedly assigned the task of collecting information from agents in neighboring Germany, he instead padded his expenses and fabricated intelligence from notional agents.
Upon the outbreak of war in September 1939, he was directed by London to identify himself to the local SIS head of station, Maj.Richard Stevens, who worked under semitransparent Passport Control Office (PCO) cover. The objective was for the two organizations to combine their resources and thereby avoid wasteful duplication, but this also eliminated the compartmentalization that had insulated the Z Organization from the hostile penetration that the PCO had experienced. Stevens, on the other hand, knew that Best, though well connected in Dutch social circles, being married to the daughter of a general, had a poor reputation and was considered rather too shrewd a businessman. Others took the view that Best was the victim of discrimination, his background being Anglo-Indian.
When Best declared himself to Stevens, he learned that the PCO had been in touch with a group of officers who claimed to be anti-Nazis plotting to overthrow Adolf Hitler. Best later said he was suspicious of the intermediaries, but on 8 November he accompanied Stevens to the German frontier at Venlo to hold a rendezvous with representatives of the opposition. The meeting was a trap, and both Best and Stevens were abducted at gunpoint and taken into German captivity, where they remained for the remainder of the war, each undergoing lengthy interrogation.
Upon their release in 1945 Best and Stevens blamed each other for having disclosed too much detailed information about the SIS, unaware that the real culprit had been an SIS colleague, Dick Ellis. The SIS did not become aware of Ellis’s duplicity until 1966, by which time Stevens had died in ignominy and a bankrupt Best had tried to make some money by publishing his memoirs, The Venlo Incident. Their interrogations had been handled with considerable skill by the enemy, who deliberately gave each the impression that the other was cooperating, without revealing the true source of the information.
The loss of two such well-informed SIS officers so early in the war was a considerable blow for the Service and a significant coup for the Sicherheitsdienst, which had masterminded the operation.
When he was questioned in 1945, Walter Schellenberg acknowledged his role, as he did later in his memoirs, The Schellenberg Papers, but was unable to identify Ellis as the SIS officer who had caused so much damage.