Towards the end of 1943, the British Intelligence services were receiving reports that captured Soviet soldiers were fighting in the Wehrmacht in Western Europe and that captured Soviet citizens were being used as slave labour in German factories, mines and farms. The Special Operations Executive (SOE), a British clandestine warfare organisation, like the British Foreign Office and MI6, had Country Sections engaged in collecting such intelligence and making plans to counteract enemy activity. Len Manderstam, a Russian-speaking officer of SOE's Russian Section who had served in the Red Army as a young man, devised Operation MAMBA, a plan to drop propaganda materials to encourage Soviet troops in the Wehrmacht to surrender to the Allies and to encourage Soviet labourers to engage in passive sabotage. In liaison with the Ministry of Economic Warfare and SOE's Forgery Section, propaganda materials were produced and dropped into France, Belgium and Holland to convince the Germans that there was an active underground Soviet resistance organisation. After D-Day, Manderstam went to France, interviewed captured Soviet soldiers and those who had surrendered and learned how the Germans had used the threat of torture and starvation to force their prisoners to fight for them. He developed a scheme to interrogate those brought to Britain as prisoners of war and recruit those who convinced him they were anti-Nazi. His plan was to train them in sabotage, parachute jumping and clandestine warfare and infiltrate groups into France to encourage Soviet defection, and others to be dropped into Germany to encourage Soviet workers to 'go slow' and others to attack Germany's secret weapons sites. As the Soviet Union was Britain's ally and there was a secret agreement between the NKVD, the People's Commissariat for Internal Affairs, they were invited to participate in Operation MAMBA. However, as Stalin had ordered Soviet soldiers to fight to the death and any who were captured were considered traitors, the NKVD refused to collaborate and raised their objections with the British Foreign Office. Bernard O'Connor's documentary history uses primary sources including letters, memoranda, telegrams and reports found in SOE files in the National Archives and secondary sources including autobiographies and biographies, newspaper articles and web pages to shed light through a British filter on this little-known operation.