The alliance between France and Britain was always a somewhat uneasy one. Sitting back and letting Britain's principal ally's army be mauled was simply not an option for Haig. If Haig had called off the offensive on 2 July, he would have thrown away this advantage. The one real achievement of the Anglo-French armies on 1 July 1916 was to relieve pressure on Verdun, as the Germans rushed troops and guns north to the Somme to counter the new threat. This reality of coalition warfare also helps to explain why Haig never contemplated halting the Battle of the Somme after the disastrous first day. At this time the French army was under heavy pressure from German attacks at Verdun. Thus in July 1916 Haig fought on the Somme largely at the behest of the French, although he would have preferred to attack, somewhat later, in the Ypres salient where there were more important strategic objectives. Naturally, the French tended to call the shots, even though the British C-in-C was an independent commander.

An inescapable fact of life for Haig and his predecessor as commander-in-chief, Sir John French, was that Britain was the junior partner in a coalition with France.

War of the lions classes