[6] The ship's machinery was based on that of the R-class destroyers,[7] with three Yarrow boilers feeding Brown-Curtiss geared steam turbines which drove two propeller shafts.

A maximum of 367 tons of fuel oil could be carried, giving a range of 3,500 nautical miles (6,500 km; 4,000 mi) at a speed of 15 knots (28 km/h; 17 mph).

[6][5] The ship was ordered in April 1916, and was initially intended to be named HMS Montrose;[9] her keel was laid down on 25 May 1916 by William Denny and Brothers of Dumbarton, Scotland.

[10] In 1936, the Admiralty recognised that the Royal Navy had a shortage of escort ships with good anti-aircraft armament, suitable for operations along Great Britain's eastern coast.

[14][15] In May 1919, Valorous was deployed with the rest of the 1st Flotilla to the Baltic Sea to participate in the British campaign there against Bolshevik forces during the Russian Civil War.

The two British ships retaliated with depth charges, severely damaging the Bolshevik submarine, which managed to escape and make it back to base at Kronstadt.

[30] Valorous suffered serious engine room flooding during operations in September 1935, and was under repair at Malta until March 1936, and was then docked at Sheerness from April to June 1936.

[28] In 1938, the Royal Navy selected Valorous for conversion into an anti-aircraft escort under the naval rearmament programme, and she entered Chatham Dockyard for the required work on 30 October that year.

[2] When the United Kingdom entered World War II in September 1939, Valorous took up convoy defence duties in the North Sea and Northwestern Approaches with Rosyth Force.

On 21 June 1941 the flotilla leader rescued the only three survivors of the tanker Vancouver, which had struck a naval mine and caught fire off Sunk Head Buoy, Harwich, with the loss of 45 lives while on a voyage from Shell Haven to Halifax, Yorkshire.

Valorous was "adopted" by the civil community of Dewsbury, then in the West Riding of Yorkshire, as the result of a Warship Week National Savings campaign in October 1941.

[2] Valorous interrupted her regular duties in January 1942 to take part in Operation Performance, deploying with the Home Fleet to cover the break-out of merchant ships from Sweden into the North Sea via the Danish straits.