Germany declares a war zone around the British Isles

On 4 February 1915 it was announced in Berlin that the waters around Great Britain and Ireland, including the whole of the English Channel, were to become a war zone. From 18 February every enemy merchant ship encountered there would be destroyed, even if, as the notice pointed out, it would not always be possible to avoid danger to the crews and passengers. The proclamation was signed by Admiral Hugo von Pohl, until then Chief of the Admiralstab, the German naval staff, who was just taking command of the High Seas Fleet. Germany was beginning its first campaign of submarine warfare directed against Britain’s merchant shipping.

Three points and a memorandum

The declaration was short. The first point established the war zone and announced that enemy ships in it would be destroyed. The second warned that neutral ships were in danger there too. Because of the misuse of neutral flags, which the British government had ordered on 31 January, and because of incidents unavoidable in naval warfare, attacks aimed at enemy ships might also strike neutral vessels. The third point stated that passage remained safe north of the Shetland Islands, in the eastern part of the North Sea and in a strip at least 30 nautical miles wide along the Dutch coast.

The declaration was accompanied by a lengthy memorandum from the German government. It accused Great Britain of waging commercial war in breach of international law: of blurring the distinction between absolute and conditional contraband and of declaring the whole North Sea a military area. It reproached the neutral states for accepting British methods too readily. Since the British invoked their vital interests, the Germans held that their own vital interests entitled them to respond in kind. The two-week interval was meant to give the neutral states time to warn their ships.

The press and official communiqués spoke of a submarine blockade of Great Britain. In the legal sense, however, it was not a blockade, since one could not be maintained with a few submarines. Germany had declared a war zone and announced that it would sink ships in it without the usual procedure of stop and search. Until then U-boats had attacked merchant ships rarely and usually in accordance with prize law, like the commander of U-17, who in October 1914 ordered the crew into the boats before sinking the British steamer Glitra. Only at the end of January 1915 did U-20 torpedo several ships without warning off the French coast.

The dispute in Berlin

The idea of using submarines against British trade had been maturing in the German navy since the autumn of 1914. Its chief advocate was Pohl. He argued that attacks on British warships achieved little, since chance played a great part in submarine successes. A strike at trade, on the other hand, could, he claimed, put pressure on Great Britain that would decide the course of the war. He urged a quick start, before the British could build up stocks of grain and raw materials. At the beginning of January 1915 Kaiser Wilhelm II still refused his consent and allowed only the preparation of boats for such operations.

The greatest doubts were held by the Chancellor, Theobald von Bethmann Hollweg. According to Pohl’s account, his concern was not international law but politics. He feared that a strike at neutral shipping would push the United States, Italy and Romania against Germany at a time when the situation on land was still undecided. He was also worried about grain supplies for occupied Belgium. Pohl replied that announcing the zone two weeks in advance and warning the neutrals would deprive them of grounds for complaint. He also gave assurances that about twenty submarines would be enough, and that the frightened neutrals would begin avoiding British waters of their own accord.

Under pressure from the navy and from a press indignant at the British blockade, the Chancellor gave way at the beginning of February. According to the diary of the head of his Naval Cabinet, Admiral Georg von Müller, the Kaiser gave his consent during a visit to Wilhelmshaven. Müller saw in this proof of the Chancellor’s weakness and of Pohl’s personal ambition. The State Secretary of the Navy, Admiral Alfred von Tirpitz, was passed over, although he himself had long favoured submarine warfare. Tirpitz advised that, out of regard for the United States, the zone should be limited to the mouth of the Thames and the waters leading to it.

Too few boats

There was no great strength behind the menacing words. At the beginning of 1915 Germany had little more than twenty submarines capable of operating in British waters, and some of them were under repair. The voyage from German ports or from the base in occupied Belgium took many days, so usually only a few boats could operate off the British Isles at any one time. The declaration relied to a large extent on its deterrent effect.

The decision also changed the role of submarines in the German navy. After the defeat at the Dogger Bank the Kaiser held the High Seas Fleet back even more firmly, and its new commander was known for his caution. The U-boats, until then used above all against warships, were now, with few exceptions, turned against trade. The burden of the naval war with Great Britain was passing to them.

A warning to the neutrals

The most alarmed were the neutral states whose ships sailed to British ports. As early as 6 February the Italian government asked the Americans unofficially what they intended to do. Norway, Sweden and Denmark agreed on a joint note of protest to Berlin. In the Netherlands, whose trade with England was very brisk, one shipping line after another suspended sailings across the North Sea and the Channel. The United States government, under President Woodrow Wilson, replied on 10 February with a sharp note, warning that it would hold Germany to “strict accountability” for the destruction of American ships or the deaths of American citizens.

In Great Britain the declaration was received with indignation as a sign that the laws of war would be broken. In March London was to respond to it, by way of reprisal, with a further tightening of the blockade of Germany. The German war zone was to come into force on 18 February 1915.