Even by the expensive standards of major defence projects, Britain's commitment to maintaining both a nuclear-weapons capability and a global naval reach over the next decades represents a substantial burden. A decision announced on 10 May 2012 illustrates the enduring problems in pursuing the second of these ambitions - and reveals anew the flaws in the ambitions themselves.
The post-1997 Labour government in Britain led by prime minister Tony Blair took the surprising decision to order two huge fleet aircraft-carriers. At over 60,000 tonnes they would be the largest warships ever built for the Royal Navy, even larger than the 1950s-vintage carriers such as HMS Eagle (see "Britain's 21-st century defence", 21 February 2007)
Since those large vessels sought to rule the waves, the navy had managed with three smaller Invincible-class carriers that could deploy with some helicopters and a few Harrier jump-jets. The proposed new carriers - Queen Elizabeth and Prince of Wales - would deploy with much larger numbers of the jump-jet version of the American F-35 multi-role aircraft. Until they were ready, probably around 2018-19, it was planned that two of the existing carriers, Illustrious and Ark Royal, would remain available.
The whole project was to run in parallel with Britain's other hugely expensive defence initiative: replacing the Trident nuclear-missile submarines. This task, over its full lifetime, would cost around £70-£100 billion. The carriers and their aircraft would be somewhat cheaper though still represent a considerable burden, not least at a time of great financial stringency. Together, the decisions would affirm that Britain intended to remain a key player in the world security game (see "British sea power: a 21st-century question", 13 July 2006).
There were many arguments against this vision of the United Kingdom's role in the world, from the economic (was it affordable?) and the moral-strategic (should Britain stay a nuclear power?) to the sustainable-security based (what idea of security will shape the century?). These, however, made no impression on the Blair outlook and both the defence projects went ahead (see "Big Boats and Bigger Skimmers: Determining Britain's Role in the Long War", International Affairs, July 2006)
The failed option
When the Conservative-Liberal Democrat coalition replaced the Labour government in May 2010, it instituted a defence and security review. The outcome was a move to upgrade the carrier project by buying a longer-range and more powerful version of the F-35, which required catapult-launching and arrester gear for landing (so-called "cat-and-traps"). The catapults would be based on a new and untried United States electro-magnetic rail-gun system rather then the tried-and-tested steam catapults used on current US carriers.
Since the carriers were already being built, all this required detailed redesign and much greater conversion costs. In conditions where money was already so tight, "something" had to give. In the event, this included the Harriers on the existing carriers and even one of the carriers itself (Ark Royal). The latter will be either disposed of (perhaps to India or China) or scrapped, while Invincible is now a helicopter-carrier.
Yet even this could not deliver enough of a cost saving. So the coalition has made an extraordinary choice: to continue to build both of the huge new warships, but commission only one - and send the other straight into storage. In the context of the delays in the carriers and the F-35, this would ensure that the Royal Navy would have no naval fixed-wing airpower until well into the 2020s; and even then the situation would resemble France's with its single carrier, Charles de Gaulle, which spends much of its time in port being repaired and maintained.
The latest element in this long-running saga is that, as many analysts anticipated, the "cat-and-trap" option has proved wildly expensive and is now being abandoned. The saving grace for the coalition (and its successors in government) is the remote possibility that by the mid-2020s, two carriers will still be available - one in service and one in reserve.
This cannot be guaranteed, however; and many within the armed forces, especially the army and Royal Air Force, remain openly sceptical about both major commitments - the carriers and Trident replacement. Moreover, the very heavy pressure on public spending over the next decade (at least) means that the question of whether the UK can even afford to be one of the "big(gish) boys" is becoming inexorable.
Many people in the Conservative Party and the defence establishment still think it is essential for Britain to maintain the status (and the self-image) of a "great power". In the coming weeks, their desire to justify this aspiration - seen as embodied in persisting with the carriers' construction - will surely be reflected in many references to China's plans for its own carriers and the Russian navy's revitalisation.
The great avoiding
The heart of the matter is indeed Britain's role in the world. In the early years after Blair's election in 1997, and particularly when from 2001 closeness to the George W Bush administration became almost an article of faith, the necessity of Britain "playing big" on the world stage was taken for granted. This required a large-scale power-projection capability provided by the aircraft-carriers, reinforced in turn by the nuclear force.
Those who during those years argued that there were far more important issues to worry about - including political violence, global marginalisation and climate change - got short shrift (see "Beyond 'liddism': towards real global security", 1 April 2010).
More than a decade on, Britain's coalition government (or at least its Conservative majority) both follows the Blair view and is obliged to cope with the legacy of his period - a bitter and destructive "war on terror". In face of this unavoidable reality, the super-carriers are more than ever marginal and Trident irrelevant. Now, the post-2008 conditions of austerity and the sheer cost of the planned new extravagances reinforce the message that the price of "greatness" is becoming astronomical. The decision over carrier-design suggests, moreover, that the search for greatness is becoming near-farcical.
A lesson of the tortuous processes over the aircraft-carriers and Trident replacement is that at some stage, a future British government would be well advised to try to work out what the best role for the UK in a divided and constrained world should be. This week's policy shift shows that that option is still unthinkable.