The purpose of SOE was to conduct espionage, sabotage, and reconnaissance in countries occupied by Nazi Germany and other Axis powers.
SOE agents allied themselves with French Resistance groups and supplied them with weapons and equipment parachuted in from England.
Brooks received the Distinguished Service Order, Military Cross, Croix de guerre, and Légion d'honneur for his work as a leader of SOE's Pimento network sabotaging German reinforcements prior to and during the Normandy invasion.
In June 1940 Nazi Germany invaded France and quickly overran the country and Brooks and his relatives joined millions of French people fleeing the Germans.
After the armistice they returned to Poligny and Brooks joined his aunt Ruth in assisting stranded British soldiers and airmen to escape from France, now occupied or under the influence of the Germans.
In May he fled his uncle's estate and journeyed to Marseilles where he briefly worked with Donald Caskie and the Pat O'Leary Line and led a group of escapees to Spain.
Brooks refused to be armed because if discovered to possess a firearm (illegal in German-controlled France) his cover story of being an average French citizen would be endangered.
She was insulted to serve in the lowly position of Brooks' courier and alienated his socialist and communist contacts with her aristocratic aplomb.
De Baissac joined her brother Claude and rendered valuable service in Normandy before and after the allied invasion of France on D-Day.
He did not want a wireless operator, vulnerable to German detection, but communicated with SOE headquarters through couriers to neutral Switzerland from where messages could be transmitted to England.
[13] Brooks received his first of many parachute drops of arms and explosives from England on 23 November 1942 and began a campaign of sabotaging railroads and electric lines.
138 Squadron on the night of 20/21 December[17] with a new cover name and the task of stockpiling weapons and explosives for use before and during the expected American and British invasion of France which would occur on 6 June 1944.
The expected invasion also stimulated a large increase in the number of French men and women willing and eager to work in the resistance.
[19] Brooks' priority before D-day was to inhibit the response of the 15,000 men and 1,400 vehicles of the 2nd SS Panzer Division Das Reich, stationed in Montaubon, to the invasion, wherever and whenever it might occur.
The key to success was to disable the railroad flatcars which would be needed to transport German tanks quickly to the invasion site.
Warned that the invasion was imminent, Pimento operatives sabotaged flatcars by putting an abrasive lubricant into their axles which froze their wheels after a few miles of travel.
[20] Historian Stephen Ambrose tells the story that some of the unguarded flatcars were sabotaged by a 16-year-old girl named Tetty, her boyfriend, her 14-year-old sister, and several of their friends.
[citation needed] He worked for the Foreign Office after the end of the war, spending time in the British embassy in Paris.