The key word in the phrase 'through deck cruiser' is 'cruiser', not 'through deck'. Cruisers were smaller and cheaper to run, as they needed neither a large air group nor a massive escort. They had a more limited role, and would not commit Britain to operations in far-flung places, being less capable at this. However, this does simplify a lot of the discussion and bureaucratic manoeuvring that happened when determining RN strategy and procurement in the 1960s and 1970s.

In the late 1950s and early 1960s, the Royal Navy was planning to reconstruct its fleet. At the time, its fleet was concentrated around modernised WWII-era ships; the carriers Ark Royal, Eagle and Victorious, and the three Tiger-class cruisers. These ships were starting to reach the limits of their capabilities compared to newer warships. They were also starting to reach the ends of their expected life-span, or would do by the time their replacements were in service. New ships were needed to replace them. The plans called for the construction of a new class of two carriers and up to five new 'escort cruisers'. The carriers would form the core of Britain's power-projection capabilities, being able to launch air strikes on targets anywhere in the world. The 'escort cruisers' were to be primarily helicopter carriers, using their embarked helicopters to attack submarines or carry troops. They would have a heavy surface-to-air armament, for area defence. These ships would mainly be used to escort the RN's carriers, freeing up space on their decks for more strike aircraft (as the carriers wouldn't need to carry ASW helicopters).

Design work on the new ships began in 1961, and continued until 1966. A large, 53,000 ton design was chosen for the new carrier. It was expected to have an air group of up to 62 aircraft, with considerable attention paid to the aircraft handling and storage arrangements. It was to be fairly fast, but as it used traditional steam turbines, would not be as fast as the USN's nuclear-powered carriers. The ship was to be given a modern radar, being developed in cooperation with the Dutch, as well as the Sea Dart surface-to-air missile system and the Ikara anti-submarine missile system for self-defence. The class would not be armoured, but were designed with extensive anti-torpedo protection. The class was designated CVA-01, with up to four ships being ordered (with another one possibly being purchased by Australia). Three of the ships were given names; the first was to be Queen Elizabeth, the second Duke of Edinburgh and the third Prince of Wales. The cruiser design had a less settled future. A design had been chosen, but the detailed design work was heavily delayed. Resources were instead being put towards the new carriers, as well as Britain's ballistic missile submarine program. The chosen cruiser design would carry five large helicopters (Chinook or Sea King) and carry Sea Dart, Ikara and a new short-ranged anti-ship missile. It would displace 10,500 tons, have a speed of 27 knots, and use the same Anglo-Dutch radar as the carriers.

The RN's new program soon ran into trouble, though. In October 1964, the Labour Party's Harold Wilson became prime minister. The new Labour government faced significant economic problems. Britain's GDP growth was sluggish compared to that of France and Germany. Productivity in British industry was low and inefficiency was high; a lot of Britain's industry was outdated, and there was a lack of capital to invest to bring it up to date. Britain was importing a lot, and exporting little, resuting in a 'balance of payments' issue that might require the government to reduce the value of the pound. In this context, reducing military spending was significant. Britain spent 6.8% of its GDP (£2.141 billion) on defence, compared to an average of 5.5% for other European countries. Reducing spending on the military would free up funds for industrial investment or for social spending. As a lot of military material was purchased from other countries, cutting military spending would also help with the balance of payments directly. Shortly after the election, the new defence minister, Denis Healey, began a review of defence spending. This review was dominated by interservice rivalry between the Royal Navy and the RAF. The RAF had a number of large, expensive projects that it wanted to keep in operation, which would also be threatened by defence cuts. However, it was more able to accept cuts to these than the Navy was. For example, the RAF's new strike bomber, TSR-2, could be replaced by purchasing the American F-111, a cheaper alternative as it would require less R&D spending. The carrier program could not be so easily replaced. The RAF also attacked the rationale behind the carriers. One of the key roles of the carrier was to provide Britain with the ability to project power 'East of Suez'; in other words, to support British allies and Britain's interests in the Indian and Pacific Oceans with an easily deployable, significant, military force. The RAF produced a set of documents laying out an 'islands strategy', which suggested that this role could be filled by RAF strike aircraft operating from bases on British or friendly territories throughout the region. The documents showed that any likely flashpoint would be within strike range; there are rumours that to do so, they lied about how far east Australia is, but there is no evidence for this. The Navy's carriers were also much less useful in what was seen as the most likely or serious war, that against the Warsaw Pact. There were fears that the carrier was obsolete, with its role being taken by guided weapons and other modern technologies. Finally, the carriers were one of the most expensive projects around. Britain had no shipyards that were big enough to build the ships, and few drydocks for them. There was a lack of designers and a perceived lack of welders for some of the specialised work that needs doing. All of these issues greatly increased the cost of the ships.

On the 14th February 1966, Healey presented the results of the Defence Review to the Cabinet. The CVA-01 project was to be scrapped, and a variety of other military cuts would be made. Britain would not retain a carrier capability after the last of the WWII-era ships was scrapped in the mid-1970s. The Royal Navy would hand over the 'East of Suez' mission to the RAF, and instead focus more on anti-submarine work in the North Atlantic. In response the Admiralty formed a Future Fleet Working Party to lay out the new fleet for this work. In July 1967, it laid out a new policy. The fleet would be built around three classes of ship: an ASW frigate (Type 22), an air defence destroyer with Sea Dart (Type 42) and a 'Command Cruiser'. The command cruiser would provide British task groups with the command and control facilities that would otherwise have been aboard the RN's carriers. It would be a link between task groups and land-based aircraft, and provide the task group with a long-ranged ASW punch using large helicopters. It would also carry Sea Dart, reducing the number of Type 42s that needed to be procured. The cruiser had strong support from Healey; Hobbs' British Aircraft Carriers quotes him stating that 'I am entirely satisfied that we must find room in our future naval plans for some ships of the cruiser type'.

Over fifty design studies were produced. These covered a variety of configurations, with the main ones being a small ship with 6-9 Sea Kings, a larger one with 9-12, and a third which carried a large sonar system. Designs were produced with a superstructure ahead of the flight deck, with it behind the flight deck, and a more traditional 'through-deck' design. The aft superstructure was rejected, as it complicated hangar arrangements. For the smaller cruiser, the forward superstructure was preferred, but for the larger design, the through-deck approach was preferred. This gave the most effective hangar layout, and was more easily adaptable should the size of helicopters rise over time. An American study which showed that at least two helicopters were needed to track and kill a modern nuclear submarine was quoted. This implied that at least seven helicopters would be needed to maintain two on station for a long period of time. As a result, the smaller cruiser was dropped. The idea of adding in the capacity to take the Harrier V/STOL (vertical/short take-off and landing) aircraft was also attractive. This would give the carrier an effective reconnaissance capability, as well as some strike and air defence capacity. As such, it was soon added into the mix. The sketch design for the new cruiser was finalised in 1970, with work being done to finalise it over the next 18 months before three ships were ordered to it.

The result was the Invincible-class. As built, they had Sea Dart for area air defence and a frigate's sonar system to find submarines for her air group to attack. They also had the extensive command and control facilities originally intended for the command cruiser. As Norman Friedman states, 'in their emphasis on command and control and in their original heavy area-defence missile armament these ships were cruisers whose main battery was ASW helicopters, supported by Sea Harriers, rather than guns'. However, over time, it became clear that these systems were impediments to their most useful capability; their aircraft. The sonar systems were removed in early refits, with Sea Dart following in the late 1990s. These refits turned them from the cruisers they had been built as, to something more akin to a light carrier.