Did the First World War do anything more than accelerate British domestic political changes that were already in progress?

The impact of the First World War on Britain in both political, economic, and social terms was immense. For the first time the general population was directly affected on a nation-wide basis by both the proximity of the conflict and the involvement that they had to make to the war effort in supporting those who were on the front lines. Unlike previous wars, when the country was somehow detached from the location and the soldiers involved, and life generally proceeded as normal, substantial changes in lifestyle by all sections of the population were needed to sustain the war effort. Thus this new scale of warfare was bound to have serious implications even after the conflict had ended. Furthermore, however, Britain was politically and socially in a period of transition in the years leading up to the outbreak of hostilities; the legacy of the Victorian era was being left behind in a social change demonstrated by the likes of New Liberalism and the suffragette movement. Overall, the changes in society, the strengthening of class affiliations and extension of suffrage to all males and large sections of the female population would by themselves have made great differences to Britain without the impact of the war. Considered against this background of change, the war confuses the picture even more, but we shall attempt to separate its impact on the political system and its more general social and economic impact.
The argument that the war acted as a catalyst for political change concerns the continued decline of the Liberal party that some argue had been in progress from as early as the turn of the century. However, the empirical evidence as demonstrated by electoral performance seems to show that the party was still in good shape, having won a landslide election in 1906, and been in power thanks to Labour support since 1910. Undoubtedly the split between Asquith and Lloyd George in 1916 proved to be the event that ensured the Liberals demise was to be a permanent one; even Asquith's forming of a coalition government was not enough to stop the attacks on his leadership, and with the struggle between him and Lloyd George brought out into the open, the Liberal party split into two factions. What would have happened without the war is obviously difficult to predict, but based on electoral performance alone, it seems that the party could have survived. Whatever ones view about the state of the party before 1914, undoubtedly the war accelerated (or indeed, was the prime cause) of its decline. In terms of Wilson's analogy1, it really doesn't matter if the man on the pavement was having a heart attack or was in the best of health - he wouldn't survive the impact of the omnibus anyway.
Coupled with the fall of the Liberals is the rise of the Labour party, but it is not simply a matter of the one replacing the other. Labour's performance in the run up to the war did not give cause to think that it was about to experience a drastic improvement in its fortunes - it must be remembered that many of the seats it had held since its formation had been won due to the co-operation resulting from the Lib-Lab pact that gave Labour a free run in many constituencies. In by-elections in three-cornered contests between 1911 and 1914, Labour failed to take a single seat, and while some label their performances as solid and consistent2, others would take a more cynical view and term them abysmal3. Certainly, they would not lead anyone to predict that Labour was to become the second largest party and become the official opposition. However, during the war, growing trade union membership meant that a larger constituency base was being formed, with a large increase in bodies affiliating to the party in 1917 and 1918. This allowed a dramatic increase in the number of candidates who could be put forward in the 1918 election, although only 15 more seats were won. However, the proportion of the vote won was more significant - 22.7%, which cannot be explained away in terms of the larger franchise, especially when it seems likely that those women voting for the first time supported the Lloyd George-Conservative coalition. However, it also seems unlikely that Labour's adoption of a socialist constitution was responsible either; socialism at this time (at any rate, the Fabian socialism of the society of that name) was viewed with deep suspicion by the trade unions. Furthermore, although Clause IV of the constitution seems a clear-cut commitment to a left-wing ideology, on closer examination, it is a fairly loose definition, and it was only after union suspicions were reassured that they accepted the constitution, something they surely would not have done if it was a commitment of the sort the Fabians were pushing for. The constitution was as much a symbolic change as one of substance, not prompted by any conversion to socialism following the experience of collectivism of some industries during the war (which was a strictly temporary measure in any case, reversed almost immediately after the Armistice); it was introduced in order to provide a clear distinction between the coalition and Labour; the war lead to Labour inheriting and assuming many of the policies and stances that had been Liberal views for much of the century. It accelerated Labour's rise through its impact on the Liberals, and Labour was to gain throughout the 1920s.
However, on another crucial issue of the time - the question of Irish Home Rule - the First World War actually delayed the resolution of the issue, rather than accelerating it. Serious with the intention of passing legislation allowing for Home Rule had been going on since the turn of the century, and a Home Rule Bill was introduced into the Commons in 1912, and became law in September 1914; however, because of the outbreak of war, it was determined that it would not be implemented until after the war was over. However, this seemingly indefinite delay seen from a republican point of view was the latest in a long series of prevarications over the question, and generated sympathy and support for both Sinn Fein and, more importantly, the Irish Republican Brotherhood (IRB). This militant republican group decided to take decisive action against British Rule, and stormed the General post Office in Dublin on Easter Monday 1916. They hoped that this would be the catalyst for a popular rising from a disaffected population that would lead to an independent Ireland - however, this rising did not develop, and the rebellion was brutally crushed. The chain of events that were set in motion by this, not least the guerrilla war conducted by the reconstituted Irish Republican Army (IRA) which grew out of the IRB, resulted in Home Rule and the creation of the Irish Free State being delayed from being officially introduced until 1921, despite the declaration of the Dail Eireann by the 73 Sinn Fein MPs elected to Westminster in the 1918 election. It seems here that the actions of the republicans in using the war's distractionary effect on Britain to launch their campaign, albeit brought on by frustration and years of waiting, only hurt their cause; many of those who supported the republican movement were happy to achieve a 26-county Home Rule system, and their actions only delayed the achievement of this (assuming that the Home Rule Law would have been implemented soon after the war had ended) by several years.
The most long-lasting and non-political impact that the Great War had was in the area of social policy. Titmuss4 argues that the South African War gave the first indication that changes would have to be made in order to be assured that in future conflict there would both a sufficient quality and a sufficient quantity of men to serve on the battlefield. Concerns had been raised in public commissions that spoke of "the gradual deterioration of the physique of the working-classes from whom the bulk of the recruits must always be drawn."5 This declining health was confirmed in the 1940s and 1950s, when increasing numbers of W.W.I veterans were forced to take early retirement as a result of their involvement in the services. The increasing demands, both physical and psychological, placed on soldiers in the new forms of warfare, coupled with the deterioration of health of the working-classes, living as they did in slum conditions of the big industrial cities, and working long hours in unhealthy conditions, prompted action on two fronts. Firstly, the government acted to improve the health of those soldiers already in service, as well as more the wider civilian population. In 1917, a scheme was introduced that can be seen as the first instalment of a National Health Service - a program whereby facilities were offered free of charge to soldiers and civilians alike for the treatment and prevention of venereal disease. Secondly, efforts were made to ensure that the health of children - who would provide the next generation of combatants - was improved. This lead to the establishment in 1906 of the school medical service, the school feeding of children in primary schools, a campaign to reduce infant mortality, and many other social measures. The necessity of such schemes was highlighted at the end of the First World War, when the Report of the Ministry of National Service declared that only one man in three of the two-and-a-half million servicemen examined was completely fit for military service.6 As well as these measures, provisions were undertaken to help the civilian population who were heavily involved in the construction of war materiel; workers in munitions factories were provided with a hot meal in the factory canteen, on the obvious assumption that doing so would improve output. There is also evidence that this helped to lower the rate of drunkenness, which would also have contributed to improved efficiency. Simple national insurance schemes and maternity benefits were also introduced to provide for the welfare of children; help was also provided for women with small children, so they could go and work in the factories. All this was geared to helping productivity among the civilian population, improving the morale and condition of the men in the trenches, and helping to build a healthier future generation of soldier who would be called on in the future to fight for their country.
The wider social impact of the war, both in terms of the general populations involvement in support of the war effort, and in the stories of horror brought back from the front by the veterans7 would take many books to detail; however, the mere existence of such literature in this area would show that it is not the case that the war had only political consequences. Many thought that the nature of the conflict would prevent a repetition at any point in the future; however, as we know, this was not to be the case.

Notes:

1) Wilson, T "The Downfall of the Liberal Party, 1914-1935."
2) McKibbin, "The Evolution of the Labour Party 1910-1924," chp. 4.
3) Wilson, T "The Downfall of the Liberal Party, 1914-1935," p. 17.
4) Titmuss, R "War and Social Policy" in "Essays on 'The Welfare State'."
5) "Report of the Inter-Departmental Committee on Physical Deterioration," 1904.
6) "Report of the Ministry of National Service 1917-19."
7) Good examples are the poetry of Siegfried Sassoon and Wilfred Owen.