On the 1st July 1916, 7.30am, after the explosion of several mines (Beaumont Hamel, Fricourt, "Lochnagar" at La Boiselle,etc) and moving close behind the barrage of the Allied artillery, the British and French infantery advanced from their trenches. The French units south of the river attacked two hours later, ad a diversionary tactic. By that evening the French 6th army under General Fayolle had reached its primary objectives. In the British sector, however, the situation was desastrous. The 3rd and 4th armies were shattered on the slopes of Thiepval and Beaumont Hamel.
Next day the number of casulties suffered on the 1st July proved to have been appalling : 58 000 men fell, including 20 000 killed. Thirty two battalions had lost
more than 500 men. The Newfounderlanders lost 700 men in 30 minutes. The left wing of the British army lost so many men that Haig briefly abandoned the attack to the west of the
July ended with a slow general advance, its uneven progress revealing the varied results of the two armies' encounters along the line.
Costly and limited attacks were launched in August, the combined French and British forces gaining control of the 2nd German line but the natureal strong-points of Thiepaval and Beaumont Hamel remained impregnable.. The German swiftly created a third line of trenches.
A general offensive was launched in September particularly to the east of Pozieres. The British launched their first tank attack and finally captured Thiepval. The German front, however, remained unbroken. The third German line was captured at the beginning of October, but the British were halted at the Butte de Warlencourt. The French were held at Sailly-Saillisel and in the wood of St Pierre-Vast, where they suffered heavy losses. Beaumont hamel did not fall to the British until mid-November.
Incessant torrential rain turned the battlefield into a morass in which men, animals and weapons were trapped. The armies took to their winter quarters and reformed their units. The British advnace, after four and a half months of battle, was, approximately 12 kilometres, and between 5 and 8 kilometres for the less numerous French. Of approximately 3 million men in the line during this period, some 1,2 million were killed, wounded or missing in action, and the allied objectives set out in December 1915 remained out of reach. The only reason for the Allied occupation of Peronne and Bapaume in March 1917 was the decision of the German High Command (determined to remain in control of its terrain, as in 1914) to order a general withdrawal to the "Hindenburg Line" (Arras-Soissons)