Who would have thought that a torpedo test ship would have such an impact on the conduct of the First World War? On 2 August 1914, the SMS Magdeburg, a German light cruiser, opened fire on the port of Libau in Latvia (now Liepaja), the first shots of the war against Russia. However, it was not until later in the month that her place in history would become more significant.
On 26 August, whilst steaming off Estonia, she ran aground and could not be freed. Two Russian cruisers appeared and seized not just the ship, but three intact copies of her code books. One of these was handed over to the Royal Navy on 13 October 1914.
The code book was the first of three different signal books the RN was to obtain by the end of 1914 for its new signals intelligence and decryption facility established in Room 40 of the Old Admiralty Building in late 1914.
With some far-sighted planning, the Admiralty ordered the German telegraph cables in the North Sea to be cut on the outbreak of war. As a result, the Germans were almost completely dependent on wireless transmissions to communicate with their ships and embassies. Britain had already begun establishing a series of wireless listening stations along the East coast prior to the outbreak of the war. With the three key codebooks, and some inspired and skilled crypto-analysis work, Room 40 soon became able to read much of the Germans’ signal and telegraphic communications, an ability that offered Britain huge strategic and operational advantages. Personnel from Room 40 went on to work at Bletchley Park during WW2.