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Room 40 – The Triumph and Tragedy of Jutland

Just after midnight on 26 August 1914, German light cruiser SMS Magdeburg ran aground in the Baltic. The crew setting off scuttling charges faced a brief engagement with the Russian Navy. The ship was seized and her destruction complete. From the ship the Russians recovered all three copies of her code book, one of which was received by the Admiralty with gratitude. With this book came the facility to ambush the Germans many times during the war, including at the Battle of Jutland.
By November 1914 a further two code books made their way to a tiny new section, created under notable scientist and engineer Sir Alfred Ewing to monitor and read German radio transmissions. A chain of intercept stations was set up along the British east coast and the team moved into Room 40 of the Admiralty Old Building, an anonymous office which was to remain the group’s name long after it had outgrown the physical space.
Room 40 was staffed by civilians and officers unfit for active service, learning the trade as they went along. Some, like Alastair Denniston and Dillwyn Knox went on to play key roles at Bletchley Park in the Second World War. 
By 1916 Room 40 had grown to about 50 strong, working round the clock seven days a week. It was not yet part of Admiral Reginald Hall’s Naval Intelligence Division but an independent bureau within Operations. 
Knowledge of the team’s activities and the information passed to ships at sea was highly restricted to prevent the Germans realising their codes were compromised. These communication gaps would prove dangerous in the unforgiving waters of the North Sea.
From May 1916 Room 40 had tracked signals indicating that the High Seas Fleet was preparing for operations. By 28 May it was clear that a major attack was imminent. At midnight Vice Admiral Scheer ordered his German warships to raise steam. On 30 May Room 40 warned that the German fleet was assembling in the Jade River outside Wilhelmshaven and that the operation would start the next day. The Admiralty alerted Admiral Jellicoe at Scapa Flow and Vice Admiral Beatty at Rosyth, enabling the Grand Fleet to put to sea three hours ahead of the enemy. Once at sea Scheer kept radio silence with his base to preserve security, Room 40 lost track of him.
At this point the first unfortunate misunderstanding occurred: Captain Thomas Jackson, Director of Operations Division and a noted sceptic paid a visit to Room 40, demanding to know the location of Scheer’s flagship. Whether downtrodden, misunderstanding or cheesed off the duty cryptanalyst answered the question literally – ‘In the River Jade’ – whereas everyone in the room knew that the call sign had been transferred to a shore station once the ship put to sea. Acting on this, Jackson misinformed Jellicoe that the main German force was still in harbour. Jellicoe saw no need to hurry to his rendezvous until Beatty, expecting to confront only Vice Admiral Hipper’s battlecruisers, ran into the entire High Seas Fleet. The experience undermined Jellicoe’s confidence in the intelligence. With key staff in Admiralty Operations Division absent or forced to rest and their substitutes inadequately briefed delays and errors snowballed. 
Consequently when Scheer’s decrypted signal ordering the High Seas Fleet home and giving a clear hint of their route reached him Jellicoe disregarded it. Several signals confirming German intentions were never passed on, and at daybreak on 1 June Jellicoe was in the wrong place to intercept the fleeing enemy.
In the wake of the confusion Ewing accepted the post of Principal of Edinburgh University. Admiral Hall brought Room 40 formally into the realm of Naval Intelligence Division, where he doubled its strength and built it into an integrated intelligence picture.
Prior to Jutland, German naval strategy was to erode the Royal Navy’s numerical advantage by luring elements of the Grand Fleet to their destruction with surface force, submarine or mine ambush. Only then would it risk a battle. Whatever tactical errors occurred, at whatever horrendous cost, Room 40 ensured this strategy never worked.
By the time a convoy system was introduced in 1917 the gap between Intelligence and Operations was narrowing. A Submarine Tracking Centre integrated all known information about U-boat and convoy movements and could redirect convoys away from danger.
The experience paid off in the Second World War. Great minds from the previous conflict were recalled and lent their experience to the new talent brought in alongside them. Personal and institutional memory ensured that many painful lessons did not have to be re-learnt.
Admiral Scheer and Admiral Jellicoe
ARW. “Hall and Godfrey-Doyens of Naval Intelligence.” The Naval Review, 1973-04: 125-138.
Beesly, Patrick. Room 40: British Naval Intelligence 1914-18. London: Hamish Hamilton, 1892.
Downing, Taylor. Secret Warriors. London: Abacus, 2015.
Hames, Admiral Sir William. “Room 40.” The Naval Review, 1966-01: 34-38.
Phimester, Jane. First World War Wireless Stations in England. Swindon: English Heritage, 2015.
Ramsay, David. 'Blinker' Hall: Spymaster. Stroud: Spellmount Limited, 2008.
Wyllie, James, and Michael McKinley. The Codebreakers: The Secret Intelligence Unit That Changed the Course of the First World War. London: Ebury Press, 2015.

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