The Type 23 class, also known as the Duke class, consists of 16 frigates.
With plans to build eight Type 26 and five Type 31 frigates under the “General Purpose Frigate” program, the British Fleet will maintain its status as one of the most powerful navies in the world for decades to come. Until then, Type 23 frigates will still have certain roles in the Royal Navy.
The Type 23 class, also known as the Duke class, consists of 16 frigates. Currently 12 are in active service with the Royal Navy and three are in service with the Chilean Navy. The lead ship, HMS Norfolk, was commissioned in 1989, and the sixteenth, HMS St Albans was commissioned in June 2002. They were designed for anti-submarine warfare, but have been used for a range of uses. The last one is expected to be retired in 2035.

The design of the class was conceived in the late 1970s. When completed, the Type 23 class had a displacement of about 4,900 tons, a length of 133.0 m, a beam of 16.1 m, and a draft of 7.3 m. It was intended to be a light anti-submarine frigate with a towed array sonar to counter Soviet nuclear submarines operating in the North Atlantic.
The ships are armed with eight Harpoon surface-to-surface missiles in two four-cell launchers and vertical-launch Seawolf. Harpoon is a medium-range anti-ship missile using inertial and active radar guidance. Seawolf is a surface-to-air missile with a command to line of sight guidance and radar and electro-optic tracking. It has a range of 6km. The Seawolf mid-life update in 2005 included an upgrade to the radar tracking system and addition of infrared tracking, with sensor fusion technology.
Other weapons include: 1 × BAE 4.5 inch Mk 8 naval gun, 2 × 30 mm DS30M Mk2 guns, 2 × Miniguns, and 4 × General-purpose machine guns. The helipad at the rear of the ship is enough for a Wildcat or Westland Merlin helicopter.
The Type 23’s original medium-range radar was replaced by BAE Systems Type 997 Artisan 3D radar. It is a medium-range radar designed to be capable of operating effectively in littoral zones and improving air-defence, anti-surface and air traffic management capabilities of the Type 23 frigates. The radar is also designed to combat complex jammers. It is claimed the radar is five times more capable than the Type 996 radar it replaces.