Morale remained surprisingly high in the British army then and afterwards, despite the losses of the first day. In 1917 French units refused to return to the front line and their commander, Robert Nivelle, was relieved of his post. The French mutinies of 1917 were not against the war, argues one historian, ‘but against the murderous way in which it was being fought’.62 Nivelle’s replacement, Philippe Pétain, restored order partly by shooting about forty mutineers (out of half a million), initiating reforms and halting frontal assaults.**9 By contrast, morale in Haig’s British army was far better than in the mutinous French and Russian armies in 1917 or the equally mutinous German and Austrian armies the following year.

The Battle of the Somme changed the war psychology of both Britain and Germany, broadening the boundaries of what nation-states felt able to inflict upon each other. After it, the Germans moved to unrestricted submarine attacks in the Atlantic, recognizing that since they probably could not defeat the British in a conventional land or sea battle they must try to starve Britain into surrender.63 When this unrestrained assault saw American commercial ships also sunk, it had the effect of bringing the United States into the war on the Allied side, with huge strategic implications. Furthermore, there could be no peace after the Battle of the Somme, except after total victory; so many men could not be seen to have died for a patched-up semi-peace.

‘Neither Haig’s view of Lloyd George nor Lloyd George’s view of Haig is likely to be accepted by history’, wrote Winston Churchill in Great Contemporaries. ‘They will both be deemed better men than they deemed each other.’64 The Somme left Lloyd George ‘deeply shaken’, as the size of the losses were unprecedented in British military history, although they were proportionately the same as those suffered by the Germans and certainly the French at Verdun, or the Union and Confederates armies at Antietam.65 ‘The horror of what I have seen has burnt into my soul,’ he told his mistress Frances Stevenson on his return from visiting a friend’s partially paralyzed son in hospital, ‘and has almost unnerved me for my work.’66 The battle left Lloyd George preferring a strategy of peripheral attacks, despite Robertson and Haig insisting that the Germans could only be defeated on the Western Front. Unable to sack Haig for political reasons, after the Somme Lloyd George instead undermined him, and by 1918 hoped to have him superseded by Pétain in the Supreme War Council.

The Battle of the Somme also brought a new degree of respect for the British army in Germany. The British-born Princess Evelyn von Blücher (née Stapleton-Bretherton), noted how much it had ‘veered round’ attitudes in Berlin. ‘Men who were scoffing and railing at England twelve months ago are beginning to express their admiration, and even dare to display a certain affection and attachment publicly.’67 In February and March 1917 the Germans, by then suffering from a severe manpower crisis, abandoned their positions on the Somme and went back to their pre-prepared ones on the Hindenburg Line 20 miles (32 km) behind the Somme front. This retreat was presented in the press as ‘an elastic bend’ in the front line, but soldiers were returning home with harrowing stories of the sheer firepower of the British artillery. The Battle of the Somme saw the pendulum of war swing in the Entente’s favour for the first time, though of course not on its first day. The Germans had retained the initiative, an all-important factor in warfare, throughout 1914 and 1915, and to an extent during the Battle of Verdun. It was at the Somme that the British and French wrested it from them for the first time, and although it was to be lost for short periods afterwards—primarily during the Ludendorff Offensive in the spring of 1918*10—the Allies retained the power of initiating the action for the rest of the war.