"The Royal Air Force 1939 - 1945- the Strategic Air Offensive" An Avro Lancaster of No 1 Group, Bomber Command, silhouetted against flares, smoke and explosions during the attack on Hamburg, Germany, by aircraft of Nos 1, 5 and 8 Groups on the night of 30/31 January 1943. This raid was the first occasion on which H2S centimetric radar was used by the Pathfinder aircraft to navigate the force to the target.