The year 1917 was one of profound change. The first two-and-a-half years of the war had settled into a depressingly familiar pattern. The predictability of the stalemate on the Western front had been mirrored by the stability of the diplomatic situation and the British home front. Any turbulence that had occurred was peripheral in that it had not threatened the status quo established by the end of November 1914.

In contrast, in 1917, while the military situation remained static, diplomatic activity and the situation in Britain became dramatically more fluid. Much of the diplomatic fluidity was inextricably linked to international events, particularly the two revolutions in Russia, while on the home front Britain witnessed the most serious industrial disruption and social discontent of the war period. Resentment grew about conscription, the increased ‘dilution’ of skilled labour with unskilled workers, and the worsening supply of basic provisions. All of these problems demanded a response from British politicians. They were operating in a party system already made highly fragile by the strains of the war. The prospects for fundamental change seemed immense.

However, despite predictions to the contrary, it was the political situation, rather than the social system or the government's military policy, which was forced to adapt to the pressures unleashed, encouraged or exacerbated by the developments of 1917. At the centre of these changes was the Labour party. After three years, in which its backing for the war had been almost entirely uncritical, the party appeared in August 1917 to dramatically change course.