Operation Fahrenheit, a raid on the semaphore of Plouézec, November 1942 By Michel Guillou, Doctor of History/ Engineer
The position of Brittany at the end of Europe and its relatively short distance from the English coasts led it to be a subject of interest for Allied strategists very quickly. We will, by developing some examples, unpublished for some of the 31 operations or
projects in this region, monitor the evolution of this British strategy across the Channel.
To ensure these combined offensive operations, the raids, it was necessary to forge new means: an element of reflection and planning, the Directorate of Combined Operations (the OP’s), a force for small raids, the Small Scale Raiding Force, specially trained personnel, commandos. The establishment of such means was possible only by the impulse given by men like Winston Churchill or Lord Mountbatten. In fact, the conventionally minded soldiers saw with a very bad eye these operations with a rather particular philosophy.
With each attempt since June 1942, interference with the operations of the secret services led to the cancellation of the small raids. The program of "Fahrenheit" around November 11, 1942 made it possible to symbolically celebrate the anniversary of the armistice and to respond positively to the aspirations of Wiston Churchill, fervent defender of these
symbols. The "Fahrenheit" operation could begin.
On the night of the 11th to the 12th, the Royal Navy fast boat MTB 344 carried a group of 11 men from the "Small Scale Raiding Force" and the "N°12 commando" to the Pointe de Plouézec in the Côtes du Nord. Their mission was to destroy the semaphore station and take prisoners in order to create trouble among the occupying forces.
During the preparation of this operation the commandos worked on aerial photos taken by the Royal Air Force and on information provided by a resistant, Claude Robinet, member of the network known as "La bande à Sidonie". In the summer of 1941 this man had already stolen, in semaphore, a map of the German defences of the Paimpol-Plouézec sector, it was transmitted to London shortly afterwards.
Feeling threatened, he clandestinely left Paimpol on January 15, 1942 for England with four other comrades aboard the "Korrigane" boat. When he arrived in England he was questioned by the Intelligence Service, he wrote a report on the German defences of the sector and drew the sketches of the semaphore buildings that were used for the development of the plan of attack of the commandos.
This event is a wonderful example of resistance cooperation with allied action service.
Secret missions and raids had completely opposite objectives. If the raids were to be effective and spectacular, the British secret services, for their part, sought complete discretion over their activities, often considering their work area as a private preserve. The success of the raid "Fahrenheit" in Plouézec could not leave
insensible to these very discreet services. This led to the end of the raids on Brittany. Thus, this operation was the only one conducted on the coastal portion between Cherbourg and St Nazaire.
_The speaker_Michel Guillou holds a doctorate in history from the University of Paris-Sorbonne and a former engineer at the University of Rennes1 Originally specialized in the history of the Normandy landings, he also conducted research, including some unpublished, on the landing and raid operations of the British Combined Operations service to the Breton peninsula (as the Fahrenheit operation in Plouézec updated 50 years after the event).
He conducted numerous studies in the 1980s and 1990s on the history of covert operations of intelligence networks (the Alibi network), escape networks (the Shelburn network) and the maritime operations of these networks in Brittany as the actions of the 15th British Secret Flotilla of which he was the correspondent for several years.
A radioelectrician by training, he also naturally addressed the problems of resistance transmissions between Great Britain and France. This is how he met Hervé Monjaret, Jean Moulin’s first radio station.