Aside from participating in the Battle of Jutland in May 1916 and the inconclusive action of 19 August several months later, their service during the First World War generally consisted of routine patrols and training in the North Sea.

Since 2002, it has been designated as a controlled site under the Protection of Military Remains Act 1986 and diving on the wreck is generally forbidden.

The failure of the Germans to agree to any sort of naval arms control caused the government to reinstate the third ship.

Three of these would be part of the St Vincent class, while the single battleship planned for the 1908–1909 Naval Programme was later authorised as HMS Neptune.

In comparison to the Bellerophon class, the displacement of the St Vincents was increased by 650 long tons (660 t), the length by 10 feet (3 m) and the beam by 18 inches (46 cm); their crews numbered about 755 officers and ratings upon completion and 835 during the war.

[4] The St Vincent-class ships were powered by two sets of Parsons direct-drive steam turbines, each of which was housed in a separate engine room.

They were rated at 24,500 shaft horsepower (18,300 kW) and were intended to give the ships a maximum speed of 21 knots (39 km/h; 24 mph).

During their sea trials, the St Vincents handily exceeded their designed speed and horsepower, reaching 21.7 knots (40.2 km/h; 25.0 mph) from 28,128 shp (20,975 kW).

This gave them a range of 6,900 nautical miles (12,800 km; 7,900 mi) at a cruising speed of 10 knots (19 km/h; 12 mph).

[4] The secondary armament of the St Vincents consisted of twenty 50-calibre BL four-inch (102 mm) Mark VII guns.

[10][Note 1] The guns had a maximum elevation of +15° which gave them a range of 11,400 yd (10,424 m) firing 31-pound (14.1 kg) projectiles at a muzzle velocity of 2,821 ft/s (860 m/s).

[4] The control positions for the main armament were located in the spotting tops at the head of the fore and mainmasts.

[15] In late 1914, the remaining rooftop guns were replaced on the three sister ships by 9-foot rangefinders protected by armoured hoods.

[16] Fire-control technology advanced quickly during the years between the St Vincents' commissioning and the start of World War I and the most important development was the director firing system.

[18] The ships were fitted with Mark I Dreyer Fire-control Tables in the transmission stations by early 1916, which combined the functions of the Dumaresq and the range clock.

Transverse bulkheads 5 to 8 inches (127 to 203 mm) thick terminated the thickest parts of the waterline and upper armour belts once they reached the outer portions of the endmost barbettes.

The stern torpedo tube was removed in 1917–1918 and St Vincent was equipped to operate kite balloons.

In 1918, a high-angle rangefinder was fitted on the forward spotting top of the surviving ships and flying-off platforms were installed on the roofs of the fore and aft turrets of Collingwood.

[22] In an attempt to lure out and destroy a portion of the Grand Fleet, the German High Seas Fleet departed the Jade Bight early on the morning of 31 May 1916 in support of Rear Admiral Franz von Hipper's battlecruisers, which were to act as bait.

The British code breakers of Room 40 at the Admiralty had decoded German radio traffic containing plans of the operation and the Admiralty ordered the Grand Fleet to sortie the night before the Germans, to cut off and destroy the High Seas Fleet.

[22][33] In the evening of 9 July 1917, Vanguard's magazines exploded while she was anchored in the northern part of Scapa Flow; she sank almost instantly, with only three survivors, one of whom died soon afterwards; 842 men aboard were lost.

She then became flagship of the Reserve Fleet in June and was relieved as gunnery training ship in December, when she was transferred to Rosyth.

The amidships portion of the ship is almost completely gone and 'P' and 'Q' turrets are some 40 metres (130 ft) away, presumably blown there by the magazine explosions.

The bow and stern areas are almost intact as has been revealed by a survey authorised by the Ministry of Defence in 2016 in preparation for the centenary commemoration planned for 2017.