'Derry' was a British special forces operation by the French 3^rd Régiment de Chasseurs Parachutistes (3^rd Special Air Service) to protect bridges near Finisterre in the Brittany north-western part of France (5/18 August 1944).

The object of the undertaking was to prevent the demolition of these vital logistics elements as General Wilhelm Fahrmbacher’s XXV Corps of General Heinrich Eberbach’s 7^th Army pulled back into the major Breton ports of Brest, Lorient and St Nazaire under pressure from Major General Troy H. Middleton’s US VIII Corps and Major General Walton H. Walker’s US XX Corps.

Under the command of Commandant Pierre Chateau-Jobert ('Yves Conan'), the 89 French troopers were parachuted into the Finisterre region and successfully protected the viaducts at Morlaix and Plougastel from German destruction as well as inflicting moderately high casualties on the Germans as Major General John W. O’Daniel’s US 3^rd Division advanced toward Brest.