Type 21

The Type 21 frigate, also known as the Amazon class, was developed as a relatively affordable general-purpose escort for the Royal Navy. Unlike many earlier British warships, it drew heavily on private shipbuilder design work from Yarrow and Vosper Thornycroft. Eight ships were built and entered service in the 1970s, forming a visible part of the fleet during the Falklands War era.

Technically, the Type 21 emphasized speed and general-purpose utility in a compact hull. Its COGOG gas-turbine machinery gave high speed, while weapons typically included a 4.5 inch gun, Sea Cat missile launcher, anti-submarine torpedo tubes, and a helicopter. The class was criticized for limited growth margin and survivability, but it remained fast, elegant, and useful for patrol and escort duties.

Operationally, the Type 21 class is closely tied to the Falklands War. HMS Ardent and HMS Antelope were lost to Argentine air attacks, highlighting the limitations of light escorts under intense missile-age air threat. Surviving ships continued Royal Navy service before being sold to Pakistan, where the class remained useful as general-purpose frigates.