The Counties are remembered for their distinctive three-funnel layout and service in all the major naval theatres of the Second World War.

[1][page needed][2] Peacetime economies and politics intervened and only two B-type cruisers were built, an 8-inch gun modified County design: the York class.

[5][page needed] These restrictions posed new engineering challenges and forced compromises upon designers in how to extract the best balance of speed, armament and protection.

[1][page needed] The United States Navy adopted a design with triple-gun turrets, allowing the hull to be shortened thus saving weight that could be put into protection.

[1][page needed] As had been tested in the First World War Emerald class cruiser HMS Enterprise, whose completion had been delayed post-war, the Counties featured a new design of forward superstructure incorporating the navigating bridge, wheelhouse, signalling and compass platforms and gunnery director in a block.

This advance considerably rationalised the separate armoured conning tower and myriad of decks and platforms of older designs.

The guns, BL 8-inch (203 mm) Mark VIII, were equally disposed in superfiring twin turrets fore and aft.

The turret design was needlessly complicated by the original requirement that they should be capable of anti-aircraft fire and were thus provided with a maximum elevation of 70°, despite the inability to train and elevate sufficiently quickly to track aerial targets and the complete lack of a suitable fire control system.

[1][page needed][6] Secondary armament consisted of four QF 4-inch (102 mm) Mark V guns in single mounts HA Mk.III fed from the amidships magazine.

Thus, the traditional side-belt of armour was dispensed with and the 1-inch (25 mm) side plating was sufficient to only give protection against shell splinters.

Originally planned as a programme of 17 Royal Navy vessels, the numbers were cut back significantly following the formation of the first Labour Government after the election of December 1923.

Cumberland and Suffolk had the aft superstructure razed and replaced by a large hangar for two aircraft and a fixed athwartships catapult.

A crane was fitted on either side of the after funnel, and the rear gunnery, navigation and control positions were relocated to the hangar roof.

Lenton expresses doubts whether the Admiralty ever informed the Government of these excesses, as with war imminent, "there were more pressing demands on their time".

The bridge was moved aft to lessen the effects of muzzle blast from B turret when the guns were trained abaft the beam.

Her upperworks were removed and replaced by new fore and aft superstructures and two upright funnels modelled on the contemporary Crown Colony-class cruisers.

A 3.5-inch (89 mm) belt, 8 feet (2.4 m) deep, was added abreast the machinery spaces, extending up to the armoured deck.

The upper deck was reinforced, which caused the stress to be transmitted through the lower hull instead and cracks began to appear under the waterline.

[1][5][pages needed] The outbreak of war prevented what had ended up being a rather fruitless cosmetic rebuild being extended to the rest of her sisters, as had originally been intended.

Shropshire, unlike her two un-converted sisters retained her torpedo armament, and was transferred to the Royal Australian Navy in early 1943 to replace Canberra.

Another two ships that had been deferred from the 1927–1928 and 1928–1929 programmes – to have been named Northumberland and Surrey – were ordered on 15 May 1929, but suspended on 23 August and finally cancelled on 14 January 1930.

An extra superstructure was added aft to carry barrage directors, fitted with radar Type 283, which finally allowed the main armament to serve in its intended anti-aircraft role.

Norfolk and Suffolk were equipped with radar which was used to good advantage when they shadowed the German battleship Bismarck during the RN's attempts to hunt her down after the sinking of HMS Hood.

Three of the class were lost, with Canberra being hit by naval gunfire at the Battle of Savo Island then scuttled by a U.S. destroyer, and Cornwall and Dorsetshire both bombed and sunk by Japanese carrier-borne aircraft during the Indian Ocean raid.