His first experience of espionage occurred in 1936 when he had been briefly employed by the Secret Intelligence Service to provide information on what he had seen in the German shipyards.
On his return to Britain, Owens had second thoughts and, in September 1938, told the British authorities of his contact and that he was to receive a radio transceiver.
The British police failed to pick him up on his return on 23 August and he used his radio to send several messages from London to Germany over the next week.
[1]: 40–43 War between Britain and Germany broke out and, on 4 September, Owens made contact with the Special Branch to volunteer his services.
Released from prison and installed in a new property with his radio and girlfriend, Owens was helped in mid September to go to the Low Countries, where he met with German agents in Rotterdam and informed them of the Chain Home stations in England designed to detect incoming aircraft.
[1]: 61 In the early months of the war, the Germans asked for regular weather reports from him for the use of the Luftwaffe and also to test his credibility; these were sent by radio.
At another meeting in Belgium with the Abwehr, this time in Brussels, Owens was given £470 in cash (the value of a house) for the Chain Home information, and some detonators for use in sabotage.
[1]: 130–142 In August 1940, McCarthy (who was working for MI5) went to Portugal and met Ritter, handing over certain "modified" documents, such as ration cards and receiving in return a new radio and £950.
[1]: 144–6 Owens helped deliver German spies to MI5, who were then given the choice of becoming double agents or facing a hangman or the firing squad.
Most chose to work for Britain, becoming double agents themselves and delivering vital information to the Allies, including details about troop movements and the keys to cracking German codes.
[1]: 164–7 During the bombing of London, Owens was moved by MI5 to Addlestone in Surrey where he lived in style on his £250 per month German salary with his girlfriend Lily Bade and their newly born baby.
[1]: 174 In February 1941, Owens was permitted to fly to Portugal to meet Ritter, accompanied by Walter Dicketts, an ex RNAS officer who had worked in Air Intelligence[3] during the previous war and had since served several prison sentences for fraud.
Dicketts was instructed by Tar Robertson, head of the double agent section in MI5, to take his WW1 Staff Appointment with the Air Ministry[3] to prove his value to the Germans, and to try and get himself taken into Germany for training.
Owens was imprisoned until the end of the war for having endangered Dicketts' life and for having revealed secret information that his pre-war German radio transmitter was being operated by MI5.
Dicketts continued to work as an agent for MI5 until 1943, undertaking a further mission to Lisbon to help an Abwehr officer defect, and spent six months in South America until March 1942.
[6] A German agent, Willem Ter Braak, had landed in November 1940 and successfully obtained accommodation and rented an office.