The class is primarily designed for anti-aircraft and anti-missile warfare and is built around the PAAMS (Sea Viper) air-defence system using the SAMPSON Active electronically scanned array (AESA) and the S1850M long-range radars.

[34] After the launch of Daring on 1 February 2006, Admiral Sir Alan West, then First Sea Lord, stated that it would be the Royal Navy's most capable destroyer ever, as well as the world's best air-defence ship.

[36][37] In 2016, it was revealed that due to a design flaw on the Northrop Grumman intercooler attached to the Rolls-Royce WR-21 gas turbines, power availability was diminished considerably when functioning in the warm climate of the Persian Gulf,[38][39] and it quickly became apparent that the class was not operating as originally envisioned.

[43] On 23 November 1999, Marconi Electronic Systems (MES), the defence arm of General Electric and in the process of merger with British Aerospace (BAe) since January, was confirmed as the prime contractor for the Type 45 project.

Duncan, the last of the Type 45 destroyers, was commissioned at Portsmouth Naval Base on 26 September 2013 and entered service in 2014 after trials and training.

[54] The Daring class is notable for being the first Royal Navy vessels to include gender-neutral living spaces to accommodate male and female crew members; communal shower and heads facilities have given way to individual cubicles, and six-person berths for junior ratings are far more flexible in accommodating a mixture of male and female sailors.

Ship's services, including hotel load and weapons system power supplies, are supplied via transformers from the high voltage supply at 440 V and 115 V.[56] The benefits of integrated electric propulsion are cited as: The key to the efficient use of a single prime mover is the choice of a gas turbine that provides efficiency over a large load range; the WR-21 gas turbine incorporates compressor intercooling and exhaust heat recovery, making it significantly more efficient than previous marine gas turbines, especially at low and medium load.

[59] In January 2016, the Ministry of Defence acknowledged that the propulsion system was (prior to upgrade) unreliable, with the BBC reporting that "total electric failures are common".

[40] While the Ministry of Defence does not release detailed information related to the number of problems experienced by the class, including total engine failure, several such occasions have been reported in the media.

[62][63][64][65][66] In November 2017, The Register reported that a Type 45 destroyer had been recalled to Britain with propeller problems, leaving the Royal Navy's traditional "east of Suez" deployment without proper warship cover.

[61] With the new diesel generators, the Type 45 needs to rely on the WR-21s only for higher-speed running and always with graceful degradation to cruising without catastrophic loss of power.

[71] The Type 45 destroyers are primarily designed for anti-air warfare, able to defend against targets such as fighter aircraft, drones, and highly manoeuverable sea-skimming anti-ship missiles travelling at supersonic speeds.

MBDA describes Aster as a "hit-to-kill" anti-missile missile capable of intercepting all types of high-performance air threats at a maximum range of 120 km.

[74] The Aster missile is autonomously guided and equipped with an active RF seeker enabling it to cope with "saturated attacks" thanks to a "multiple engagement capability" and a "high rate of fire".

[75] In May 2014, Jane's Information Group reported that the United Kingdom is committing more funds to explore the capabilities of the SAMPSON multi-function radar and the Type 45 destroyer in a ballistic missile defence role.

This followed a successful live firing event at the Ronald Reagan Ballistic Missile Defense Test Site, Kwajalein Atoll in the Western Pacific Ocean, where Daring demonstrated the ability to "[detect] at the earliest opportunity, with tracks maintained through to intercept" two medium-range ballistic missile surrogate targets.

[76] Due to the greater capabilities of the Type 45 over predecessors, the high price per ship, and the public attention they have attracted, defence analysts and correspondents have referred to them as the "most advanced" or "most powerful" air-defence destroyers in the world.

A block 2 version of the Aster 30 NT capable of intercepting 3,000 km (1,900 mi) range missiles is under development by France and Italy.

[84] Planned upgrades In July 2021, it was announced that the destroyers' anti-air armament will be enhanced with the addition of a 24-cell silo for Sea Ceptor surface-to-air missiles.

[31][94] The Wildcat relies on the ship's sensors in attacking submarine targets since, in RN service as of 2019, it lacks dipping sonar or sonobuoys of its own.

[101] In November 2022, it was announced that the Royal Navy will receive the Naval Strike Missile (NSM) to replace Harpoon, which will be fitted to Type 45 destroyers.

In the same theatre of war, the United States Navy ship, USS Carney, has shot down 14 drones, most likely, using her main gun which is a much cheaper method.

[117] The MoD's initial planning assumption was to procure twelve ships on a like-for-like replacement of a similar number of Type 42s, with the size of the second batch to be determined between 2005 and 2010.

[119] This plan was officially abandoned on 19 June 2008 when the Minister for the Armed Forces, Bob Ainsworth, announced in Parliament that options for the seventh and eighth destroyers would not be taken up.

Its main conclusions were that despite the destroyer being based on 80% new technology, there was a failure to take sufficient account of technical risk, over-optimism, and an inappropriate too-early fixed price project entered into before many elements had been specified.

The Ministry of Defence said it was "unusual but not unprecedented" and that "All Type 45 destroyers are currently in port as they have either just returned from operations or are about to be deployed, are conducting training or carrying out maintenance or are home for crew to take summer leave.

"[123] In an interview with the Sunday Times, former Rear Admiral Chris Parry claimed that the Type 45 destroyers are noisy ships that can be heard 100 nautical miles (190 km; 120 mi) away by submarines.

[125] In response to a written question in the House of Commons on 19 July 2021, Jeremy Quinn Minister of State, Ministry of Defence, detailed the status of the Type 45 destroyers as 4 undergoing refit in the UK, one being repaired abroad having been forced to detach from the CSG21 formation and one active with CSG21.

The remaining Type 45 names, Dauntless and Dragon, were most recently carried by D-class (or Danae-) light cruisers of 1918, which served until 1945.

[137] In January 2024, James Cartlidge, the Minister of State for Defence Procurement, responded to a written question, saying that the last destroyer will retire from service by the end of 2038.