The Prosper Network, also called the Physician Network, was the most important network in France of the Special Operations Executive (SOE) in 1943. SOE was a secret British organization in World War II. The objectives of SOE were to conduct espionage, sabotage, and reconnaissance in occupied Europe and Asia against the Axis powers, especially Nazi Germany. SOE agents in France allied themselves with French Resistance groups and supplied them with weapons and equipment parachuted in from Britain.

An SOE network in France (also called a circuit or a reseau) usually consisted of three agents: an organizer and leader, a courier, and a radio operator. Prosper, based in Paris, grew to be much larger. The Prosper Network began in September 1942 when Andrée Borrel parachuted into France, followed by leader Francis Suttill, code named "Prosper," a few days later. Suttill had early success in finding French supporters willing to oppose the German occupation of France. Prosper soon had links from the "Ardennes to the Atlantic" in northern France with 30 SOE agents and hundreds of French associates. The destruction of Prosper began with the capture by Germans of Suttill and others in June 1943 and continued for months afterwards. SOE French Section headquarters in London, headed by Maurice Buckmaster and Nicolas Bodington, was slow to recognize that Prosper had been destroyed. SOE radios captured by the Germans were used to deceive SOE headquarters. Most of the captured SOE agents and many of their French associates were executed. SOE agents captured by the Germans were customarily treated with the Nacht und Nebel (Night and Fog) policy by which they disappeared without a trace into German concentration camps or were executed with no records being kept as to their fate.

The literature about the Prosper network is large and theories, often conspiratorial, abound about the reasons for the fall of Prosper and its aftermath. The conclusions of M.R.D. Foot in his official history of SOE's F (French) Section were that the disaster was caused by the incompetence of SOE agents in France and gullibility of SOE leaders in London, plus the work of an alleged double agent, Henri Déricourt. Sarah Helm's conclusions were that the errors were due to "terrible incompetence and tragic mistakes". Mark Seaman cited also the "efficient practices" of the German security forces. The opposing view, advocated by a few, is that Prosper was deliberately sacrificed by the British intelligence services as part of Operation Cockade to mislead the Germans about allied plans for the invasion of Nazi-occupied Europe. The reasoning behind the deception was that if the Germans anticipated an invasion of France in 1943, they would maintain or expand their occupation forces in western Europe, rather than sending resources east to combat the advancing Soviet Army. According to this theory, the Germans interpreted the rapid expansion of SOE in France in 1943 as a prelude to invasion that same year. (The invasion didn't take place until June 1944.)

1942

8 September. Itinerant French pilot France Henri Déricourt arrived in the United Kingdom after being smuggled out of France by the Pat O'Leary Escape Line. He was investigated by MI5 (Security Service) which said that it was "unable to guarantee his reliability." Despite those concerns he was subsequently recruited by MI6 (Secret Intelligence Service) before having his name and credentials passed to the Special Operations Executive (SOE) in November 1942. Déricourt's old friend, Nicolas Bodington, now the second in command of SOE's French section, endorsed his employment enthusiastically. 25 September. Courier Andrée Borrel parachuted into France, landing near the town of Crouy-sur-Cosson, southwest of Paris. Borrel was the first female agent of SOE to arrive in France by parachute. She was met by SOE agents Yvonne Rudellat and Pierre Culioli, who posed as a married couple. 2 October. Organiser Francis Suttill, the leader of Prosper, was dropped blind (without a reception group) by parachute near La Ferté-sous-Jouarre, east of Paris. Parachuting with him was Jean Amps, a horse groom who was to work for Suttill. Suttill hurt his knee on landing. He proceeded to Paris to meet Borrel in a cafe she was familiar with. Reunited with each other, the couple embarked on a tour of northern France, masquerading as a brother and sister who were selling agricultural equipment, and utilizing a list of contacts supplied to SOE by the Carte network which operated mostly in southern France. 31 October. Radio operator Gilbert Norman parachuted into France near Crouy-sur-Cosson. Norman carried with him a poison pill to kill Pierre Culioli, as SOE agent Raymond Flower had accused Culioli of being a double agent. None of the SOE agents was willing to administer the pill. Flower also attempted to get rid of Rudellat by leaving incriminating items in her room. Culioli was furious at this attack on his character and loyalty. He and Ruddelat broke off relations with Flower, joined Suttill, and created the small Adolph Network which became a sub-network of Prosper. Flower was later withdrawn from France by SOE at the request of Suttill. 8 November. Allied military forces invaded French possessions in North Africa and in response the Germans occupied the previously-unoccupied portion of southern France called Vichy France or the "Free zone." Life for SOE agents in southern France became more dangerous, but most of Prosper's operations were in northern France. mid-November. Traveling by train to Paris, André Marsac, a courier for the Carte network (a failed predecessor to Prosper), had his briefcase stolen by a German agent. The briefcase contained the names and personal information about more than 200 Carte supporters. The Germans continued to observe Carte, but did not take immediate action to arrest those people on the list. Suttill would unknowingly be in contact with many people on the Carte list as he built the Prosper network. 18 November. Prosper received its first air drop of guns, grenades, and plastic explosive. Suttill, Borrel, Rudellat, and Norman were at the drop site near Étrépagny, northwest of Paris. The arms were distributed to resistance groups, including communists who were numerous and well-organized in the northern suburbs of Paris. 30 December. Jack Agazarian parachuted into France to join the Prosper Network as a second radio operator. He was later joined by his wife Francine, a courier. They were one of only a few married couples working for SOE.

1943 (January to June)

23 January. Henri Déricourt, code named Gilbert, was dropped by parachute into France near Orleans. He proceeded to Paris where he joined his wife and, unlike most SOE agents, lived under his own name as he was a well-known pilot. Déricourt was designated as the air movements officer for Prosper, finding landing fields for clandestine flights from Britain, sending off and receiving passengers on those flights, and receiving supplies and messages. He acted also as a postman, collecting uncoded messages from agents in France for SOE Headquarters in London. Déricourt is alleged to have been a pre-war friend of Karl Bömelburg, the Gestapo head in Paris. 18 March. Déricourt accomplished his first air operation successfully. Two Westland Lysander airplanes landed at night on a clandestine field near Poitiers and dropped off four agents and boarded four more for return to Britain. Déricourt arranged successful landings in France for 11 Lysanders by the end of June. 22 April. Sisters Germaine and Madeleine Tambour were captured in Paris by the Germans. Germaine had been the secretary for the now-defunct Carte network. Ten SOE agents had used the Tambour's house as a letter box and meeting place, violating SOE doctrine that agents should have limited contact with each other. Suttill attempted to free the sisters by bribing the Germans with one million francs, but the Germans deceived him by releasing two prostitutes instead. The Tambour sisters were later executed in Ravensbrück concentration camp. 15 May. Francis Suttill departed France by clandestine flight to London for consultations with SOE Headquarters, especially F Section Leader Maurice Buckmaster. According to Buckmaster, SOE wanted to quell growing French expectations of an allied invasion of France in 1943. However, Buckmaster contradicted himself in another book by saying that he received a top-secret hint that the invasion would take place in 1943. Historians have speculated that he told Suttill to increase the activities of his network to support the anticipated 1943 invasion (which did not occur until June 1944). In either event, Suttill's mood was grim. He criticized SOE headquarters for its mistakes, cited problems within his network, and said the network may have been penetrated by the Germans. 17 May. Two Dutch men, Richard Christmann and Karl Boden, posing as SOE agents but belonging to the German Abwehr, arrived at a Paris cafe asking for "Gilbert" (Déricourt), and requesting evacuation to Britain. Without attempting to verify the bona fides of the bogus Dutch agents, several legitimate SOE agents met with them. The incident is significant because it illustrates the lack of attention to security by Prosper agents and the ease by which the network could be infiltrated. 21 May. Francis Suttill arrived back in Paris after his visit to SOE Headquarters in London Some historians claim that Suttill had been told in London that an allied invasion of France was imminent and that he should accelerate arming the resistance to assist the invasion. Supporting this speculation was the fact that SOE greatly expanded the number of air drops of weapons to Prosper and other SOE networks in June. 12 June. Suttill told friends "somebody who had enjoyed my trust must be a double agent." 13 June. At an airdrop in the Sologne region one or more canisters full of arms and ammunition exploded arousing German attention. Pierre Culioli requested Suttill to halt the near-nightly air activities in the Sologne as a result of the increased German presence. Suttill refused and the landings and airdrops continued. The Germans set up checkpoints around the area. 16 June. Two Canadian agents, Frank Pickersgill and Ken Macalister, parachuted into the Sologne region near where the explosion had occurred on 13 June. They were met by Pierre Culioli and Yvonne Ruddelat. The Canadians brought with them several messages for other SOE agents and crystals for Gilbert Norman's radio. Their SOE-forged identification papers were out of date and they remained in hiding while Culioli had new documents made. 17 June. Radio operator Noor Inayat Khan, arrived in France by Lysander airplane. She was met by Henri Déricourt. On 20 June Gilbert Norman radioed SOE that Noor had arrived in Versailles near Paris. Inayat Khan initially worked for France Antelme and later Êmile Garry. 21 June. Culioli and Ruddelat intended to drive Pickersgill and Macalister to Beaugency to catch a trail to Paris, but in Dhuizon they were stopped by Germans and Macalister and Pickersgill were captured. Culioli and Ruddelat attempted to flee in the automobile, but, chased by Germans, Ruddelat was shot in the head and Culioli crashed into a wall. Both survived the crash and were captured. Culioli had a list of names and addresses of SOE agents and supporters in his briefcase. Ruddelat died of mistreatment and illness in Belsen concentration camp about 23 April 1945, after the camp had been liberated by Allied forces. Culioli survived the war in Buchenwald concentration camp. Pickersgill and Macalister were executed in Buchenwald on 14 September 1944.