One of the transformers destroyed during the attack (German Federal Archives)
In May 1941 the Special Operations Executive (SOE) received a request to sabotage the power station in Passaic near Bordeaux but the French Section had no agents available: most had already been deployed to France on various operations and others were still being trained at the school for advanced industrial sabotage in Hertfordshire. SOE HQ then approached the Polish Section (EU/P) which came under the jurisdiction of the Polish Government in Exile in London, and after agreeing to undertake the mission six Polish volunteers boarded a converted Whitley bomber of No.138 Special Duty Squadron at RAF Tempsford to infiltrate France by parachute.
Shortly after entering French air space the aircraft suffered an electrical fault which caused their container loaded with weapons and explosives to be jettisoned over the Loir and were forced to abandon their mission and return to England. Unbeknown to the aircrew the electrical fault was far more serious than first thought and eventually caused the aircraft to crash land and catch fire at RAF Tempsford: all the crew were either killed or injured and the six Polish agents suffered serious burns.
SOE HQ then asked RF Section (the Free French equivalent to SOE under General de Gaulle) whether they were willing to attack the power station and after de Gaulle agreed, on the night of 11-12 May 1941 three agents from RF Section, J Forman, Raymond Cobard and André Vernier (aka Jacques Leblanc) successfully infiltrated France by parachute.
After hiding their weapons and explosives the team reconnoitred the power station: there was a high-tension cable very close to the top of a 9-foot wall they needed to climb over and it appeared there was a large number of German and Italian soldiers protecting the power station. They also failed to obtain the bicycles they intended using for the getaway so decided to postpone the attack.
Before leaving England Forman was given the Paris address of an RF agent called Joêl Letac who remained in France after a failed mission called Operation Savanna, the elimination of Luftwaffe Pathfinder crews whilst they travelled by coach to their airfield, and after meeting Forman Letac encouraged him to continue the mission and the following day Letac travelled with the sabotage team to the power station. After the old lorry they obtained broke down they continued the remainder of the journey on stolen bicycles and eventually recovered the equipment they had buried around 100 yards from the power station.
On the night of 7-8 June 1941 during pitched darkness due to the blackout Forman climbed the perimeter wall and crawled under the high-tension cable which was dangerously close. After ensuring he could not be seen by the guards Forman entered the compound and opened a side door, the rest of the team entered the grounds of the power station and then sprinted across open ground to the main building.
In less than thirty minutes the team placed magnetic incendiary devices on eight large electricity transformers and then made their getaway on the stolen bicycles. It has been said the explosions were so violent flames rose high into the air and illuminated the entire area and searchlights started probing the sky for bombers.
Seven of the transformers were destroyed and this seriously disrupted the Bordeaux submarine base, numerous factories used to supply the German military were forced to stop production for several weeks. The electricity grid from another region was diverted but the overload caused more damage and all electric trains in south western France had to be replaced with steam locomotives, and all the transformer oil in France was used during the repairs.
Some writers claim the team was picked up by a RAF Lysander of 161 Special Duty Squadron, but this was not the case. The team arrived in France with one million francs (said to be about £1,400 in 1941 and roughly £71,000 in 2021) and the money was unaccountable! Instead of requesting an extraction they remained in France for a further two months and according to historian MRD Foot “They left behind them broken glass and broken hearts” before escaping to England via neutral Spain. Before they crossed the frontier Cabard was captured but later escaped and returned to England.