The D class as they were known from 1913 was a fairly homogeneous group of torpedo boat destroyers (TBDs) built for the Royal Navy in the mid-1890s.

They were all constructed to the individual designs of their builder, John I. Thornycroft & Company of Chiswick, to meet Admiralty specifications.

In 1913 the nine surviving "30 knotter" vessels with two funnels (all ten had been built by Thornycroft, but Ariel was lost before their renaming as D class) were retrospectively classified by the Admiralty as the D class to provide some system to the naming of HM destroyers.

All were powered by triple expansion steam engines for 5,700 indicated horsepower (4,300 kW) and had coal-fired water-tube boilers, except for the final vessel (Stag) in which the engine power was slightly raised to 5,800 ihp (4,300 kW).

The 30-knot torpedo boat destroyers built by Thornycroft were referred to as two funnel – 30-knot ships and were not assigned a class name at the time.