The ‘Bogey has come at last’, noted the Sussex solicitor and polymath, Edward Heron-Allen, in his diary at midnight on 3 August 1914. During his thirty years as a professional lawyer, he reflected, ‘when people consulted their legal and financial advisers about the highest classes of “gilt-edged” investments, they always asked the stereotypical question “Is it perfectly safe?” and we always shrugged our shoulders and replied “Unless there is a European war!” – meaning that this was utterly beyond the possibility of belief’.

The bogey had come. But the Great Powers had not somehow ‘slithered over the brink’ without apprehension as if in a fit of absentmindedness, as Lloyd George put it so evocatively in his war memoirs. War had come as a result of individual decisions and a rapid series of moves and countermoves by the chancelleries of Europe, and set against the backdrop of recent shifts in the international landscape and anticipated further changes in the years to come. The Powers did not operate in a vacuum. If, in 1914, there was no formal and largely institutionalized framework of international politics of the kind that exists today at different levels, there was nevertheless a system of Great Power politics – the European concert, with its norms of behaviour, accepted rules of conduct, and conflict-solution mechanisms.