HMS Ajax was the third of four King George V-class dreadnought battleships built for the Royal Navy in the early 1910s.

Aside from participating in the failed attempt to intercept the German ships that had bombarded Scarborough, Hartlepool and Whitby in late 1914, the Battle of Jutland in May 1916 and the inconclusive action of 19 August, her service during World War I generally consisted of routine patrols and training in the North Sea.

The King George V-class ships were designed as enlarged and improved versions of the preceding Orion-class battleship.

She carried enough coal and fuel oil to give her a range of 6,310 nautical miles (11,690 km; 7,260 mi) at a cruising speed of 10 knots (19 km/h; 12 mph).

[4] Like the Orion class, the King George Vs were equipped with 10 breech-loading (BL) 13.5-inch (343 mm) Mark V guns in five hydraulically powered twin-gun turrets, all on the centreline.

[5] The King George V-class ships were protected by a waterline 12-inch (305 mm) armoured belt that extended between the end barbettes.

[10] Ordered under the 1910–1911 Naval Estimates,[11] the ship was laid down by Scotts Shipbuilding & Engineering at their shipyard in Greenock on 27 February 1911 and launched on 21 March 1912.

[12] She was completed a year later at a cost of £1,889,387,[2] but was not commissioned until 31 October 1913, joining her sister ships in the 2nd Battle Squadron (BS).

The squadron departed for gunnery practice off the northern coast of Ireland on the morning of 27 October and the dreadnought Audacious struck a mine, laid a few days earlier by the German auxiliary minelayer SS Berlin.

On the evening of 22 November 1914, the Grand Fleet conducted a fruitless sweep in the southern half of the North Sea; Ajax stood with the main body in support of Vice-Admiral David Beatty's 1st Battlecruiser Squadron.

[16] The interned German ocean liner SS Kronprinzessin Cecilie, HMS Princess, served as a dummy for Ajax from 1 November 1914 until 9 January 1916 when she began her conversion into an armed merchant cruiser.

[18] As the 2nd BS was departing Scapa Flow in the darkness, Ajax collided with a trawler, but suffered no significant damage.

The Germans got the better of the initial exchange of fire, severely damaging several British destroyers, but Admiral Friedrich von Ingenohl, commander of the High Seas Fleet, ordered his ships to turn away, concerned about the possibility of a massed attack by British destroyers in the dawn's light.

[20] Jellicoe's ships, including Ajax, conducted gunnery drills on 10–13 January 1915 west of the Orkneys and the Shetland Islands.

Almost three weeks later, Ajax participated in another fleet training operation west of Orkney during 2–5 November and repeated the exercise at the beginning of December.

On the night of 25 March, Ajax and the rest of the fleet sailed from Scapa Flow to support Beatty's battlecruisers and other light forces raiding the German Zeppelin base at Tondern.

On 21 April, the Grand Fleet conducted a demonstration off Horns Reef to distract the Germans while the Imperial Russian Navy relaid its defensive minefields in the Baltic Sea.

They enforced strict wireless silence during the operation, which prevented Room 40 cryptanalysts from warning the new commander of the Grand Fleet, Admiral Beatty.

The British only learned of the operation after an accident aboard the battlecruiser SMS Moltke forced her to break radio silence to inform the German commander of her condition.

Vice-Admiral Sir John de Robeck, Commander-in-chief of the Mediterranean Fleet, hoisted his flag in Ajax on 18 April and the ship sailed to the Caucasus to allow him to investigate the situation there as the Bolsheviks advanced.