Of in the initial attack, into no man's land, ten rushed from the British front trench and twelve advanced at a steady pace behind a creeping barrage. Prior and Wilson found that the behaviour of the British infantry had less effect than the behaviour of the German infantry, which in turn was determined by the fire of the British guns. Where the German defences and garrisons had been destroyed, the British infantry succeeded. When significant numbers of German machine-gunners survived, especially when supported by artillery, the British attack failed. On the French front, the artillery preparation was almost wholly effective in destroying German defences and killing German infantry in their underground shelters. The prevalence and effectiveness of killing-machines determined the result and in such an environment, a soldier with a bayonet was obsolete and infantry formations irrelevant. In 2009, J. P. Harris described the success of the French and of XIII Corps and XV Corps, the extent of British casualties for ground gained and Haig's responsibility for the British casualties. Harris wrote of the inferior German defences on the French front, surprise, superior French artillery and better infantry tactics than those used by the British. The French attacked in the south as did the two most successful British corps and in this area, only the first line was expected to be captured. Harris wrote that the German 2nd Army was often ignored in analyses of the First Day and that the main defensive effort was made in the north, the area of greatest German success. Terrain in the south, Anglo-French air superiority and closer objectives, tended to concentrate Allied artillery-fire, which was better-observed and more accurate than on the hillier ground to the north. In the south, barbed wire was cut, the German fortifications were "exceptionally" damaged and a crude form of creeping barrage preceded the infantry to their objectives. Harris held Haig responsible for the extension of the objectives in the north to the German second position, which diluted the density of British artillery-fire, although no study had been made of the details of the preliminary bombardment and caution must accompany a conclusion that bombardment of the closer objectives was unduly dissipated. Harris concluded that the attack front was too broad and that Rawlinson should be held responsible with Haig for attempting to advance on a front. Despite being under no diplomatic pressure from the French or political pressure