Binding the powers

At the beginning of the 20th century, Britain had struggled in its three-year war with the Boer republics of South Africa, and realised that it needed not just to reform the army but also to tackle issues of finance, public health and colonial government.

The reforms it initiated were designed to enable it better to deal with the responsibilities of imperialism, up to and including war. A sequence of international agreements created regional balances and so mitigated the consequences of global responsibility.

Greater issues revolved round the balance of power in Europe.

In 1901, the Hay-Pauncefote Treaty accepted American domination of the western Atlantic. In the following year, Britain and Japan entered an alliance which enabled Britain to offset its fears of Russia in the Far East.

Anglo-French hostility, so often the leitmotif of both sides' foreign policies for the previous two centuries, was finally buried with an entente in 1904. Ostensibly this settled the two powers' rivalries in North Africa and the Mediterranean, but increasingly what was designed as a settlement of colonial disputes came to carry European connotations.

This process was made even clearer with the fourth and final stage of the process, the entente with Russia in 1907. At one level this laid to rest Britain's long standing fears about the security of India from attack on its north western frontier.

At another, it completed the creation in Europe of a Triple Entente to match the Triple Alliance of Germany, Austria-Hungary and Italy. Germany's attempts to rupture the Entente, principally through engineering crises over Morocco in 1905 and 1911, had the reverse effect.

They bound the powers tighter together and convinced them that colonial clashes had to be subordinated to the greater issues revolving round the balance of power in Europe.

Sea power

This was the underlying dynamic which explained Britain's entry to World War One. Formally speaking, Britain was not under any obligation to support France, let alone Russia, in a war with Germany.

Indeed, the first response of the foreign secretary, Sir Edward Grey, was to call on Germany to cooperate in convening a conference of the great powers. When Germany refused, Grey confronted the fact that imperial obligations and European policy were indivisible.

Politically, Britain could not afford to alienate either France or Russia, given its reliance on them for the system of global security which it had constructed. Strategically, its maritime power meant that it could not permit a mighty and hostile European power to dominate the Low Countries and so threaten the English Channel.

The implication was that Britain would wage war as a sea power.

Germany's invasion of Belgium became the mechanism by which such thoughts could be rendered in popular and more universal terms: great power politics were presented as ideologies.

The implication was that Britain would wage war as a sea power, which was exactly how Grey made his case to the House of Commons on 3 August 1914.

The French government was even more anxious to ensure that Britain honoured the Anglo-French naval agreement of 1912 - which had left the defence of France's northern coast in the hands of the Royal Navy - than to secure the despatch of a British Expeditionary Force to the continent.