attack on the D Line was to be made by the 107th Brigade with three battalions. The attacking battalions were to advance in eight waves at intervals and the 107th Brigade was to advance in artillery formation until resistance was met. Battle 1 July At four hours after dawn, the Irish troops formed up in no man's land, most along the sunken Thiepval–Hamel road, obscured by the bombardment and smoke screens on the flanks and moved to within of the German front trench. The artillery and mortar bombardment lifted off the front trench at and the Irish advanced steadily, crossing the front trench with few losses but then the German counter-barrage fell on the rear of the first line and the support companies. As soon as the British guns stopped, machine-gun fire from Thiepval cemetery swept the support battalions as they moved forward and fire from Beaucourt Redoubt across the Ancre, caught the third support battalion on the left flank. The foremost infantry pressed on, reached the B Line at and took a large number of prisoners but German troops emerged from dugouts in the A Line behind the 108th Brigade, where the moppers-up had been killed by machine-gun fire. The leading waves continued to advance and reached the C Line and the corner of Redoubt at The supporting battalion survivors had occupied their objectives but cross-fire from German machine-guns then prevented movement. Reserve IR 99 of Reserve Infantry Brigade 52, holding the line north of Thiepval, was broken through and the attackers rushed Redoubt around The garrison, a support company standing by to reinforce the front defences, was surprised and surrendered after brief resistance. The centre battalion of RIR 99 had been destroyed in the breakthrough and taken prisoner. An attack towards the Grandcourt Line ran into the British barrage, then fell back to Redoubt and the which ran from the redoubt down the north edge of the ridge to the Ancre. The left hand battalion of RIR 99 had repulsed the attack on Thiepval but the centre and right, from the village to the Ancre south of St Pierre Divion, had been broken through, most of the troops having been trapped underground and taken prisoner. Observers in the Grandcourt Line were unable to see the breakthrough and over-running of the redoubt and the because of smoke and dust in the air. Only when the Irish advanced on the