Of all the world’s naval powers, only a handful operate aircraft carriers, and fewer still maintain more than one. The United States leads with eleven nuclear-powered supercarriers. China operates three. Beyond them, only the United Kingdom, Italy, and India each maintain two fixed-wing carrier-capable ships in active service. This places Britain in a very small strategic circle — one that reflects both considerable ambition and considerable expense.
The strategic case for carriers rests on their mobility and independence. Unlike land-based airpower, a carrier requires no access to foreign territory, no agreement from host governments, and no fixed infrastructure. It can position itself within striking range of a crisis, sustain air operations for weeks, and withdraw as quickly as it arrived. For a country with global interests and treaty commitments spanning NATO and the Indo-Pacific, this kind of self-contained, mobile airpower is not easily replaced by any other platform.
HMS Queen Elizabeth was commissioned on 7 December 2017 and HMS Prince of Wales on 10 December 2019. Both belong to the Queen Elizabeth class, each displacing around 65,000 tonnes at standard load and measuring 284 metres in length — the largest warships ever built for the Royal Navy. The propulsion system uses integrated electric propulsion, driven by two Rolls-Royce MT30 gas turbines and four Wärtsilä diesel generators, giving a top speed of around 25 knots. One of the class’s most distinctive design features is its twin island superstructure: a forward island for navigation and ship operations, and an aft island for flight deck control. This arrangement, unusual among carriers of this size, spaces out the exhaust funnels, reduces wind turbulence over the flight deck, and provides redundancy if one island is incapacitated. The flight deck is fitted with a ski-jump ramp for Short Take-Off and Vertical Landing operations, accommodating up to 36 F-35B Lightning II fighters in wartime, alongside Merlin helicopters for anti-submarine warfare and airborne early warning. The core ship’s company numbers around 679, rising to approximately 1,600 when the air wing is embarked — a notably lean crew for a vessel of this displacement. The total programme cost stands at around £6.2 billion for the two ships, with full lifecycle costs estimated above £9 billion.
Compared with the leading carrier fleets, the Queen Elizabeth class occupies a middle tier. The American Gerald R. Ford class displaces 100,000 tonnes, stretches 337 metres, and is driven by two nuclear reactors to speeds exceeding 30 knots. It carries an Electromagnetic Aircraft Launch System enabling it to operate the full range of US carrier aircraft, including the E-2D Advanced Hawkeye fixed-wing airborne early warning aircraft. France’s Charles de Gaulle, at 42,000 tonnes, is smaller but similarly nuclear-powered, and also CATOBAR-configured, allowing it to operate the Rafale M fighter and fixed-wing early warning aircraft. Britain’s choice of ski-jump STOVL design reduced the complexity and cost of the build — the government abandoned a mid-programme switch to catapult configuration in 2012 when retrofit costs doubled to an estimated £2 billion — but the trade-off is a more restricted aircraft inventory. Most significantly, without catapult and arresting gear the carriers cannot operate fixed-wing airborne early warning aircraft, leaving a gap in beyond-visual-range situational awareness that the Merlin Crowsnest helicopter system only partially fills. On crew efficiency, however, the British ships compare well: the Charles de Gaulle requires around 1,800 combined naval and air personnel for a 42,000-tonne ship, while the Queen Elizabeth class needs fewer people to operate a vessel half as large again.
Britain built two carriers rather than one for a specific institutional reason. Aircraft carriers require regular dry-docking, and maintenance periods lasting many months are unavoidable. A single-carrier fleet cannot guarantee continuous deployment readiness. Two ships allow the Royal Navy to rotate: one at sea on operations, the other in upkeep or standby. This is what defence planners call continuous carrier strike capability — the assurance that at any given moment, at least one carrier can respond. It was this logic, reaffirmed in the 2015 Strategic Defence and Security Review, that justified the cost of building and maintaining both vessels.
The propulsion system has been the source of the most serious difficulties since commissioning. Each carrier’s propeller shafts are too large to be machined from a single piece of metal and are instead manufactured in three sections joined by shaft couplings. In August 2022, HMS Prince of Wales suffered a failure of the starboard shaft coupling less than a day after leaving Portsmouth, and had to be towed back to port. Divers found that the 33-tonne propeller had malfunctioned, with the coupling that held it in place broken. The ship went to the Babcock shipyard at Rosyth for repairs lasting nine months. An investigation found that the starboard shaft had been misaligned during the build stage and that key components had been incorrectly installed — faults that went undetected throughout sea trials. In February 2024, HMS Queen Elizabeth was forced to withdraw from NATO’s Exercise Steadfast Defender when pre-sailing checks identified a fault on her own starboard shaft coupling. HMS Prince of Wales sailed in her place at short notice. The Ministry of Defence maintained that the two incidents were unrelated, but both ships were built under the Aircraft Carrier Alliance, a consortium of contractors including BAE Systems, Babcock International, and Thales UK, and the quality control questions raised by investigators were never fully resolved in public. Parliamentary figures show that HMS Prince of Wales spent only around 21 percent of her time at sea from commissioning to 2025, with approximately a third of that period in repair.
It is against this background that the simultaneous downtime of both carriers in early 2026 has to be understood — because simultaneous downtime is precisely what the two-carrier design was meant to prevent. HMS Queen Elizabeth entered the Rosyth dry dock in mid-2025 for a major refit covering the propulsion system, navigation controls, and damage control systems. The work was expected to take around seven months, but proceeded more slowly than planned and remained several months behind schedule into 2026, with no confirmed return-to-service date. HMS Prince of Wales, meanwhile, had led the carrier strike group on Operation Highmast, an eight-month deployment to the Indo-Pacific covering over 40,000 nautical miles, returning to Portsmouth at the end of November 2025. Following any extended deployment a warship requires a maintenance period before it can sail again. The result was that one carrier’s refit overran its schedule while the other was completing post-deployment maintenance, and the two windows overlapped. The rotation mechanism that justified the two-carrier programme had broken down.
Even if both ships were simultaneously in good mechanical order, a further structural constraint would remain. A carrier cannot deploy into a contested environment without a protective screen of escort vessels. In early 2026, parliamentary data showed that only three of the six Type 45 destroyers were mission-ready, six of the eight Type 23 frigates were available, and just one of five Astute-class nuclear submarines was at sea. Across a total fleet of 63 vessels, roughly half were available for duty. Even with two healthy carriers, the escort fleet could not sustain two full carrier strike groups simultaneously.
In March 2026, as tensions escalated in the Middle East, Britain reduced HMS Prince of Wales’s readiness notice from fourteen days to five, signalling that she could sail rapidly if ordered toward the eastern Mediterranean. The decision confirmed that the carrier retains its value as a strategic instrument. But it also made clear that only one of Britain’s two flagship carriers was in a position to respond — the other remained in a Scottish dry dock, its return date uncertain.
Britain’s decision to build two Queen Elizabeth-class carriers was structurally sound: two ships ensure rotation, rotation ensures continuity. The difficulty is that the logic depends on assumptions — that refits complete on schedule, that build quality holds across both hulls, that the escort fleet remains sufficient to support deployment — which have not consistently held in practice. A carrier is not a capability in isolation. It is the centrepiece of a system, and when the supporting elements of that system fall short, the continuous carrier strike capability the programme was designed to deliver becomes, at best, intermittent.
