Vanguard's first task after completing her sea trial at the end of 1946 was, early the next year, to convey King George VI and his family on the first Royal Tour of South Africa by a reigning monarch.

Using four existing twin 15-inch mountings offered the possibility of bypassing this bottleneck and allowed the construction of a single fast battleship more quickly than building more Lion-class ships.

The turrets were originally built for the battlecruisers Courageous and Glorious during the First World War, and were removed during the conversions of these ships to aircraft carriers in the 1920s.

[6][7] Design work was suspended on 11 September 1939, after the start of the Second World War, but resumed in February 1940 after the First Lord of the Admiralty, Winston Churchill, expressed an interest in the ship.

Greater fuel capacity was added and the armour protection improved, but these changes deepened the design's draught to beyond the 34-foot (10.4 m) limit of the Suez Canal.

The ship had already been ordered on 14 March[9] under the 1940 Emergency War Programme,[10] although the drawings were not turned over to John Brown & Company until ten days later.

The longitudinal distance between the inboard and outboard propellers was increased from 33.5 to 51.5 feet (10.2 to 15.7 m) to reduce the chance of a single torpedo wrecking both propeller shafts on one side and watertight access trunks were added to all spaces below the deep waterline to prevent the progressive flooding through open watertight doors and hatches that had happened to Prince of Wales.

The Director of Naval Construction stated that doing so along the lines of the Audacious class would present no major difficulties but would require six months to redesign the ship.

Steam heating was provided for her armament, instruments, look-out positions and other equipment to make Vanguard suitable for operations in the Arctic.

[15] To save design time, the four-shaft unit machinery from the Lion-class battleship was duplicated with alternating boiler and engine rooms.

There were two director control towers (DCT) for the 15-inch guns, each carrying a "double cheese" Type 274 fire-control radar for range finding and spotting the fall of shot.

[12] The ship's armour scheme was based on that of the King George V class with a thinner waterline belt and additional splinter protection.

[29] Originally the belt armour was equal to that of the older ships, but it had to be reduced to offset weight increases when the design was modified to reflect wartime experience.

[32][33] Intended to resist the impact of a 1,000-pound (450 kg) armour-piercing bomb dropped from a height of 14,000 feet (4,300 m), Vanguard's deck protection was identical to that of the King George V class, six-inch non-cemented armour over the magazines that reduced to 5 inches (127 mm) over the machinery spaces.

[21][31] Vanguard's underwater protection was enhanced when she was redesigned in 1942 to reflect the lessons learned when Prince of Wales was sunk by Japanese torpedo bombers.

The longitudinal bulkheads of the side protection system were raised one deck higher to further subdivide the spaces behind the waterline armour belt.

[42][43] The Admiral's suite was reworked into accommodations for the Royal Family and their staff while the anti-aircraft mount on top of 'B' turret was replaced by a saluting platform.

Initially escorted by the destroyers Orwell, Obedient, Offa, Opportune, and Rotherham, the ship rendezvoused with the Home Fleet on 1 February 1947 to receive a 21-gun salute led by the battleships Nelson and Duke of York, and the aircraft carrier Implacable.

[42] Vanguard arrived in Cape Town on 17 February, escorted by the South African frigates Good Hope, Transvaal and Natal on the last leg of her voyage.

Vanguard became the flagship of Admiral Sir Arthur Power, Commander-in-Chief of the Mediterranean Fleet, on 1 March 1949, and the ship made port visits to Algeria, France, Italy, Cyprus, Libya, Lebanon, Greece and Egypt before she arrived back at Devonport on 21 July.

While returning from a brief training sortie to Gibraltar, Vanguard went to the aid of a small French merchantman whose cargo had shifted in a severe storm on 13 February 1950.

After manoeuvres with Indomitable, during which her aircraft "sank" the battleship, the ship made port visits in Genoa and Villefranche-sur-Mer before returning for a brief refit in Devonport on 14 March.

Four months later the admiral transferred his flag to the carrier Indefatigable as Vanguard began another refit in preparation to again become the flagship of Home Fleet.

[48] Buckingham Palace announced in November that King George VI was planning to take a short cruise for his health aboard Vanguard, which meant that her Admiral's suite again had to be modified to accommodate him and his staff.

Captain John Litchfield assumed command on 21 December while the ship was still refitting, but the King died on 6 February 1952 before he could make his cruise.

[51] Admiral Sir Michael Denny replaced Creasy as Commander-in-Chief, Home Fleet, on 5 January 1954 and Vanguard participated in Exercise Medflex A with Dutch and French ships in March.

During the rest of the year she participated in anti-submarine and anti-aircraft exercises as well as making port visits to Oslo and Kristiansand in Norway and Helsingborg in Sweden.

On 4 August 1960, when the ship was scheduled to be towed from Portsmouth to the breaker's yard at Faslane, Scotland, the whole of the Southsea sea front was packed with people who came to see her off.

She was pulled off by five tugboats an hour later, and after nearly running aground again near the Moving & East pub on the opposite shore, made her final exit from Portsmouth.

[55] As a part of the scrapping process, sections of 150-millimetre-thick (5.9 in) pre-atomic steel plate uncontaminated with radionuclides were recovered from Vanguard and used for the shielding of the whole body monitor at the Radiobiological Research Laboratory (now DSTL) at Alverstoke, Gosport, in Hampshire, England.