its relief on 11 July the 17th (Northern) Division had suffered The 18th (Eastern) Division was relieved by the 3rd Division on 8 July, with since 1 July. By noon on 11 July, the 23rd Division was relieved by the 1st Division, having lost up to 10 July. The 30th Division had another in five days, after only a short period out of the line. The 34th Division had the most casualties of any British division involved in the battle, losing from 1 to 5 July, which left the 102nd and 103rd Brigades "shattered". From 5 to 12 July, the 38th (Welsh) Division had In 2013, Ralph Whitehead recorded that in the casualty reporting period from 1 to 10 July, the 2nd Army suffered casualties, and sick. Subsequent operations The Battle of Bazentin Ridge (14–17 July 1916) was an attack by the Fourth Army which began at dawn and marked the start of the second phase of the Battle of the Somme. Sceptical French officers had called it "an attack organized for amateurs by amateurs". British preparations for the offensive included a close watch on German rail and road movements; on 6 July a British pilot bombed and set on fire a troop train unloading near Vélu, rail traffic at Cambrai and Marcoing was reported later that day. Flights over Landrecies and Le Cateau found no unusual rail movements but on 7 July many trains were seen on the lines from Cambrai and Bapaume to Roisel, which indicated that troops were being moved to the south bank of the Somme. On 8 July rail movements diminished, on 9 July traffic between Lille and Douai showed troops moving down from Flanders and on 10 July traffic diminished again. By 12 July aircraft and balloon reports revealed that the German line between Thélus and Lens was being thinned and troops moved south from the Lille area. German artillery had moved back to new positions during the Battle of Albert and the British air-observers methodically located and registered many of the new emplacements. The attack of 14 July gained tactical surprise and was "hugely successful", unlike the disaster north of the Albert–Bapaume road on the First day on the Somme. A preparatory bombardment had begun on 11 July, in which of front line and of other trenches, about the ground bombarded before 1 July, was shelled by the guns, an intensity five times