Home-grown terrorists equipped by a foreign power are not a new phenomenon. During the Second World War, Hitler's Germany made sustained efforts to inflict a terror campaign on the streets of Britain through the use of secret agents and agents provocateurs. The aim was to blow up military, industrial, transport and telecommunication targets, to lower morale among the civilian population and disrupt the war effort. Even before the outbreak of war, the Nazis provided the IRA with assistance for their plan to sabotage the British mainland. Prior to their planned invasion in the summer of 1940, the Nazis were also keen to recruit members of the Welsh and Scottish Nationalist Parties to engage in sabotaging British targets and, over the course of the war, infiltrated dozens of trained agents from countries including Norway, Denmark, Holland, France and Cuba. What happened to the myriad plots to blow up Britain? We know that intelligence obtained from decrypted enemy messages via Bletchley Park and double agents like ZIGZAG, SUMMER and TATE alerted MI5 to some of these spies' arrivals, but what about the others? And how successful were MI5's efforts to fake acts of sabotage and arrange media coverage to fool the enemy into thinking their agents were still at large and on task? In this book, Bernard O'Connor, a noted wartime espionage historian, tells the complete story of the successes and failures of the Nazi terror offensive on mainland Britain during 1938-1944.

RAF Tempsford, a remote Second World War airfield between Cambridge and Bedford, was designed by an illusionist to give over-flying enemy pilots the impression it was a disused airfield. Home to the RAF's Special Duties Squadrons, it was only used on the clear nights on either side of the full moon. Flying low and without lights, brave pilots and aircrews carried many hundreds of tons of arms and supplies to resistance groups north of the Arctic Circle, east to Czechoslovakia and Poland, southeast to the Balkans and south as far as the Pyrenees and Italy. 'The Tempsford Academy' tells the story of William Stephenson, the man sent by Roosevelt to assess Britain's potential to resist German invasion in 1940, his meeting the men running Britain's secret service and being shown round SOE's training facilities, weapons, R&D sites etc. He persuaded the President to send William Donovan, subsequent head of OSS (what became the CIA), to see how the Americans could establish an intelligence network in London. Offices were set up in London and establishments for the training and deployment of US secret agents into occupied Europe as well as assisting the SOE in supplying the resistance. Until an airfield was built for their clandestine operations, agents were flown out from RAF Tempsford: Churchill's Most Secret Airfield.

Following the German invasion of the Soviet Union in June 1941, Churchill and Stalin secretly agreed that Britain would infiltrate Soviet agents into occupied Western Europe. Liaison began between the NKVD and the SOE, each country's secret service. Transported in convoys across the Arctic Ocean and often attacked by German U-Boats, thirty-four men and women arrived in Scotland. To stop people finding out that Britain was helping the Communists, the agents were given false identities and provided with accommodation and training at remote country houses in southern England, including Beaulieu. Codenamed PICKAXES, they were sent for parachute practice at Ringway aerodrome, provided with documents, cover stories and wireless sets and sent on clandestine missions into France, Belgium, Holland, Austria, Germany and Italy. Whilst most were sent from RAF Tempsford, Churchill's Most Secret airfield, one was sent by boat across the Channel and another by submarine into Northern Italy. Only a few survived the war as most were caught, interrogated and executed. Based on extensive research, Bernard O'Connor tells their human stories enmeshed in a web of political intrigue and diplomacy.

Nearly forty female agents were sent out by the French section of Britain's Special Operations Executive (SOE) during the Second World War. The youngest was 19 and the oldest 53. Most were trained in paramilitary warfare, fieldcraft, the use of weapons and explosives, sabotage, silent killing, parachuting, codes and cyphers, wireless transmission and receiving, and general spycraft. These women - as well as others from clandestine Allied organisations - were flown out and parachuted or landed into France on vital and highly dangerous missions: their task, to work with resistance movements both before and after D-Day. Bernard O'Connor uses recently declassified government documents, personnel files, mission reports and memoirs to assess the successes and failures of the 38 women including Odette Sansom, Denise Colin, and Cecile Pichard. Of the twelve who were captured, only two survived; the others were executed, some after being tortured by the sadistic officers of the Gestapo. This is their story.