The new jump jets would be much more capable than Harrier, and the carriers much larger than the Invincible Class they replaced. But some, particularly in the Navy, hankered for the prestige and capability that catapult carriers bring. Catapult carriers are the biggest of big orchestras in naval warfare, the Blue Riband standard – and naturally enough, some in the Royal Navy wanted that for Britain.

However, as well as the lack of steam on the ships, these carriers also come with a host of additional costs and complexities not easily afforded by our Armed Forces, which have been retrenching since the peak of the Cold War in the mid-1980s.

Still, those who hoped that catapults might one day be an option engineered an increase in the size of the ships from 40,000 to 65,000 tonnes to leave room to install the equipment. 

The Strategic Defence and Security Review of 2010 was widely criticised for cutting the size of the UK’s armed forces, but one area where there was investment was in the aircraft carriers, by now being built in yards all around the UK.

A new technology, electromagnetic launch, was being developed in the US. Britain’s carriers could provide power to run it.

The advocates of catapult carriers seized their moment and persuaded Liam Fox, the defence secretary at the time, and then-prime minister David Cameron, to switch from a jump jet carrier to a catapult carrier using the new system. Costing for the change was sought, but numbers were needed very quickly, right at the end of the review. 

The estimate said that it would cost between £750m and £1bn to buy one set of the catapults. These would have to be inserted into the second carrier, Prince of Wales, as the first, the Queen Elizabeth, was too far ahead to be practically changed.