HMS Velox was a turbine-powered torpedo boat destroyer (or "TBD") of the British Royal Navy built on speculation in 1901-04 by engineering firm Parsons Marine, with the hull subcontracted to Hawthorn Leslie and Company at Hebburn on the River Tyne.

The British Admiralty, eager to investigate the use of steam turbines in warships, ordered the experimental destroyer Viper from Parsons Marine in 1898, and purchased Cobra, also turbine-powered, built as a private venture by Armstrong Whitworth, in 1900.

[1] Both ships were quickly lost however, with Viper running aground off Alderney on 3 August 1901,[2][3] and Cobra broke in half while on her delivery voyage on 19 September 1901.

[3][4] The Admiralty was still keen to adopt turbines, and so decided to buy a turbine-powered destroyer that was being built as a private venture by Parsons, the Python.

[b] A new feature was that a pair of small triple expansion engines (rated at 150 indicated horsepower (110 kW) each) that could be coupled to the inner, low-pressure turbine shafts for efficient cruising.

[15] In May 1909, Velox was passing Lands End when her port engines failed and heavy rolling caused a loss of feedwater supply to her condensers.

After this incident, Velox was transferred from normal flotilla duty to be attached to HMS Vernon, the Royal Navy's torpedo establishment as a training vessel.

[28] On 25 October 1915, the ship was on patrol with the destroyer Conflict when condenser problems forced Velox to seek calmer waters near the Isle of Wight.