Joan Miller was born in 1918. After leaving boarding school at 16 she found work in an tea-shop in Andover. This was followed by the post of an office girl at Elizabeth Arden. Later she was promoted into the Advertising department.
Just before the outbreak of the Second World War Miller joined MI5. At first she worked under Lord Cottenham who headed MI5's transport section. However, it was not long before she was recruited by Maxwell Knight, the head of B5b, a unit that conducted the monitoring of political subversion. Knight explained he wanted her to spy on the Right Club. This secret society was an attempt to unify all the different right-wing groups in Britain. Or in the leader's words of "co-ordinating the work of all the patriotic societies".
In his autobiography, The Nameless War (1955), Archibald Ramsay , the founder of the Right Club, argued: "The main object of the Right Club was to oppose and expose the activities of Organized Jewry, in the light of the evidence which came into my possession in 1938. Our first objective was to clear the Conservative Party of Jewish influence, and the character of our membership and meetings were strictly in keeping with this objective."
By 1940 Miller had become one of the most important figures in the Right Club. Maxwell Knight asked Miller to keep a close watch on Anna Wolkoff who was suspected of being a German spy. Wolkoff ran the Russian Tea Room in South Kensington and this eventually became the main meeting place for members of the Right Club.
In February 1940, Anna Wolkoff met Tyler Kent, a cypher clerk from the American Embassy. He soon became a regular visitor to the Russian Tea Room where he met other members of the Right Club including its leader, Archibald Ramsay. Wolkoff, Kent and Ramsay talked about politics and agreed that they all shared the same views on politics.
Kent was concerned that the American government wanted the United States to join the war against Germany. He said he had evidence of this as he had been making copies of the correspondence between President Franklin D. Roosevelt and Winston Churchill. Kent invited Wolkoff and Ramsay back to his flat to look at these documents. This included secret assurances that the United States would support France if it was invaded by the German Army. Kent later argued that he had shown these documents to Ramsay in the hope that he would pass this information to American politicians hostile to Roosevelt.
On 13th April 1940 Anna Wolkoff went to Kent's flat and made copies of some of these documents. Joan Miller and Marjorie Amor were later to testify that these documents were then passed on to Duco del Monte, Assistant Naval Attaché at the Italian Embassy. Soon afterwards, MI8, the wireless interception service, picked up messages between Rome and Berlin that indicated that Admiral Wilhelm Canaris, head of German military intelligence (Abwehr), now had copies of the Roosevelt-Churchill correspondence
Soon afterwards Wolkoff asked Miller if she would use her contacts at the Italian Embassy to pass a coded letter to William Joyce (Lord Haw-Haw) in Germany. The letter contained information that he could use in his broadcasts on Radio Hamburg. Before passing the letter to her contacts, Miller showed it to Maxwell Knight.
On 18th May, Knight told Guy Liddell about the Right Club spy ring. Liddell immediately had a meeting with Joseph Kennedy, the American Ambassador in London. Kennedy agreed to waive Kent's diplomatic immunity and on 20th May, 1940, the Special Branch raided his flat. Inside they found the copies of 1,929 classified documents including secret correspondence between Franklin D. Roosevelt and Winston Churchill. Kent was also found in possession of what became known as Ramsay's Red Book. This book had details of the supporters of the Right Club and had been given to Kent for safe keeping.
Anna Wolkoff and Tyler Kent were arrested and charged under the Official Secrets Act. The trial took place in secret and on 7th November 1940, Wolkoff was sentenced to ten years. Kent, because he was an American citizen, was treated less harshly and received only seven years. It is said that after being sentenced Wolkoff swore that she would get revenge by killing Miller.
Miller also worked in a special department of the Post office that was set up to read letters being sent by perceived subversives. Miller and another agent, Guy Poston, were given the task of breaking into the home of Rajani Palme Dutt, a leading member of the Communist Party in Britain. Maxwell Knight was interested in a locked box that he kept under his bed. However, when they opened the box they discovered it only contained documents about his wedding.
After the conviction of Anna Wolkoff and Tyler Kent, Miller began living with Maxwell Knight. However, she soon realised she was being used as a cover for Knight's homosexuality. She left Knight and married Tom Kinlock Jones in June, 1943.
Miller now transferred to the Political Intelligence Department (PID). This involved reading and distributing top-secret cables. While in this post she identified a spy who was passing the contents of some of these cables to the Soviet Union. She was later transferred to a unit that controlled the contents of newspapers being distributed in Germany.
Joan Miller died in June 1984. Despite efforts by MI5 Miller's daughter managed to get her mother's autobiography, One Girl's War: Personal Exploits in MI5's Most Secret Station, published in Ireland in 1986.