Britain modifies the Declaration of London

On 20 August 1914 the British government issued its first Order in Council concerning the Declaration of London. Britain announced that in wartime it would observe this agreement, but with its own additions and modifications. In practice these changes considerably extended its ability to control maritime trade.

A convention that never was

The Declaration of London, signed in 1909, was meant to codify the law of naval warfare, including the rules on contraband and blockade. Britain signed it but never ratified it. Many in London felt that it restricted the powerful British fleet too much. After the outbreak of war the neutral states, above all the United States, asked the belligerents whether they would apply the Declaration.

The doctrine of continuous voyage

The most important change concerned so-called conditional contraband, that is, goods that could serve both the civilian population and the army, such as food or fuel. Under the Declaration these could be seized only if they were bound directly for enemy ports. The British decided that they would also confiscate them when a ship was sailing to a neutral port, if the ultimate recipient of the goods was the enemy’s authorities or army.

This was the so-called doctrine of continuous voyage, known from the time of the Napoleonic Wars. It allowed cargoes bound for the neutral Netherlands or Denmark to be seized if it could be proved that they would in fact end up in Germany.

Significance

The order of 20 August was an important step in building the naval blockade of Germany. It provoked protests from the neutral states, especially the United States, which defended the right to free trade. In the following months Britain gradually introduced further changes, and in 1916 it abandoned the Declaration of London altogether. The blockade, ever tighter, became one of the Allies’ most important weapons in this war.