along with 77 Squadron. The two squadrons were a part of 4 Group Bomber Command. In January 1940 the leaflet policy was changed, and Bomber Command was freed to begin bombing raids against targets in Germany in earnest. No. 77 Squadron undertook its first bombing mission against a German target on 19 March, when it was flown against the German sea plane base at the southern tip of the island of Sylt. In the coming months Marks was engaged on raids on variety of disparate targets, including Posen, Prague, Warsaw, Hanover, Trondheim and Oslo, and was mentioned in despatches "for gallant and distinguished services." In May 1940 German forces invaded the Netherlands, Belgium and France. British bomber forces did what they could to stem the German advance, but were largely ineffective. On 20 May whilst attacking bridges in France Marks' aircraft was hit by flak and the plane's hydraulic system was knocked out. He lost the use of his flaps, but he was still able to land his aircraft, though his ground speed at landing was much higher than normal. The following night 21 May he participated in a raid against Cologne and returned on one engine. For the rest of the month he was involved in attacking German transport support, striking Quesney Cross-roads in France on 23 May, Walcheren on 25 May and the Neuss railway junction on 27 May. On 1 June 1940, Marks was awarded the Distinguished Flying Cross (DFC). According to his citation, he "has shown tenacity of purpose, a high courage and thoroughness of planning and execution which is beyond praise." In the early days of the war it proved difficult to attack targets from the air with a conventional bomber due to a tremendous lack of accuracy. During the daytime such targets as railway junctions and cross roads could be located and attacked, but individual vehicles and other small targets could not be because bomber aircraft simply lacked the ability to deliver bombs with that kind of precision. It was much more difficult at night. Even attacking larger targets such as road junctions and troop concentrations was not effective. Flying in the dark of night each aircraft was in its own world. They were unaware of the position of other bombers around them, were unable to see them, and with the target itself shrouded in darkness it was very difficult for the squadron to