For the Royal Navy, the First World War was a bittersweet experience. Although it ended with the defeat of the German High Seas Fleet, Britain's Grand Fleet did not claim the decisive victory over its German counterpart for which public opinion clamoured. There was no repeat of the Battle of Trafalgar. The war at sea was decided by other, less glorious aspects of naval strategy.

In the early stages of the war, the two fleets fought a number of small-scale battles. Any chance of a German invasion of Britain receded after the Grand Fleet's victory at the Battle of Heligoland Bight on 28 August 1914. Five months later, with the help of a German codebook fortuitously captured by the Russians, it again inflicted substantial damage on the High Seas Fleet in the North Sea at the Battle of Dogger Bank. However, neither of these victories, nor more distant triumphs such as the Battle of the Falklands (8 December 1914), proved decisive.

The great set-piece battle that the Grand Fleet desired finally took place on 31 May 1916, when it clashed with the High Seas Fleet at the Battle of Jutland. After it was over, Britain still controlled the sea, and Germany never again attempted a full-scale naval confrontation. However, the number of British casualties was more than double Germany's, and much of the High Seas Fleet had retreated successfully to base. Both sides thus claimed Jutland as their triumph. British public opinion, as Vera Brittain remarked, was unsure whether it was 'celebrating a glorious naval victory or lamenting an ignominious defeat'.

Britain ultimately won the war at sea through two strategies that had little in common with full-scale battles such as Jutland: the trade blockade and the convoy system.

Britain used its naval dominance to shut off German access to the North Sea. From November 1914, ships from neutral countries entered this British 'military area' at their own peril. Germany was thus prevented from receiving vital war supplies and foodstuffs throughout the conflict.

This trade blockade inflicted on the German population levels of privation unknown in Britain during the war - not least starvation, which killed just over 88,000 in 1915, rising to more than 293,000 in 1918. This contributed greatly to Germany's eventual collapse in 1918.

Submarine warfare

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Lusitania

By the spring of 1917, Germany's newly introduced policy of unrestricted submarine warfare was sinking one in every four ships coming to Britain. Belatedly and reluctantly, the Royal Navy introduced a convoy system to protect Allied shipping from submarine attacks. The new strategy worked immediately. By 1918, shipping losses at the hands of enemy torpedoes were declining rapidly.

Submarine warfare led to high death tolls (an estimated 15,000) among seamen of the merchant navy. The merchant fleet undertook a number of tasks vital to British success: carrying essential supplies to Britain from the empire and Dominions, transporting troops and supporting naval ships.

The seamen - particularly 'Lascars', Asians taken on as cheap labour in colonial ports - frequently had to endure harsh conditions. These men made up more than a fifth of the total killed.

British dominance of the sea and the indirect pressure that the Grand Fleet brought to bear on the German war effort, particularly through the blockade, were vital to the Allied victory - which may explain the muted response of the British naval élite when, on 21 November 1918 and in accordance with the recently signed armistice, much of the German High Seas Fleet sailed into the Firth of Forth in Scotland to surrender. As the British commander-in-chief, Admiral Sir David Beatty, allegedly remarked: 'This is very nice, but I would give them three salvoes' start for a fight.'