The key decision on whether or not to replace the submarines that carry the Trident nuclear weapons system will have to be made almost immediately by the next UK government.
Production contracts for the next generation of submarines are due to be awarded some time in 2016. That makes the political decisions made after May 7 central to whether the UK remains in the exclusive nuclear weapons club for the long term.
Defence minister Michael Fallon has already launched a blistering attack on Labour, warning that Ed Miliband would “barter away” Trident under pressure from the SNP if voted into government.
This followed a pledge by Nicola Sturgeon to make Trident a red-line issue in any post-election negotiations. She vowed that SNP representatives would not, under any circumstances, agree to continue a UK nuclear weapons capability.
While all the parties involved in this election seem to have firm – and rather varied – positions on Trident, none is likely to engender meaningful change. It is highly likely that the Vanguard submarines that carry the Trident nuclear-armed missiles will be replaced.
At the moment, the UK operates a policy of “minimum nuclear deterrence”. It maintains just enough nuclear weaponry to deter an attack from an enemy.
It has a fleet of four Vanguard-class nuclear-powered submarines. At least one of these stealthy 150-metre, 16,000-ton boats is on patrol at all times somewhere underneath the ocean, ready to hit targets anywhere in the world – a posture known as continuous at-sea deterrence.
Each submarine can theoretically carry up to 192 independently targetable nuclear warheads, each with a potential yield of 100 kilotons (several times that of the bombs dropped on Hiroshima and Nagasaki in 1945). However, the government decided in 2010 that this should be limited to a maximum of eight missiles carrying 40 warheads per boat.
If a decision is made to build the new submarines, they would be due to be available by the late 2020s. They would gradually replace the existing fleet, providing the UK with a sophisticated retaliatory nuclear weapons capability well into the 2050s. The Trident missiles – which are “leased” from the United States – will not need to be upgraded or replaced until at least the 2040s.
Where the parties stand
A Conservative majority at the election would almost certainly mean like-for-like replacement of the fleet, including four new submarines.
A Labour victory would probably mean something similar – it was after all the last Labour government that began making the case for like-for-like replacement back in 2006. While it is possible this might be based on a reduced posture, such as three rather than four submarines, shadow chancellor Ed Balls seems to have committed Labour to maintaining continuous at-sea deterrence. This is despite concerns from some Labour MPs about the cost of replacement.
The Liberal Democrats are critical of a like-for-like replacement, arguing that the threats to the UK have changed markedly since the Cold War – when Trident was originally set up.
That said, they are at least nominally committed to the findings of the 2013 Trident Alternatives Review, which said that Trident is the most cost-effective option for nuclear deterrence. The Lib Dems may propose reducing the number of submarines and discontinuing continuous at-sea deterrence, but with submarines available for deployment on a contingency posture.
Pressure from the left
Things will get more interesting if the smaller parties come away with more influence in the government. The Scottish National Party has made its position abundantly clear, even if Ed Miliband has ruled out any formal coalition agreement.
The Greens and Plaid Cymru have joined the SNP in raising their objections to Trident and all three have suggested that the system would be a key issue for any possible coalition agreement. Although UKIP seems to be supportive of replacement, it has appeared uncertain in the past.
The most likely outcome – be it a Conservative or Labour-led government – is replacement and continuous at-sea deterrence. While the type of governing agreement Labour and the other parties reach would be important, it is likely that there would be a cross-party majority for Trident replacement in the House of Commons. So ultimately, opposition from the SNP or anyone else might come to very little. Had the Scottish referendum resulted in independence, the Trident base at Faslane could well have been lost, but that is no longer the issue.
Ultimately, despite the hype, the most likely scenario appears to be that, barring a shock result on the May 7, the next UK government will make the decision to remain in the nuclear weapons business well into the second half of this century.
So while the political manoeuvring will be fascinating, this election is highly unlikely to lead to nuclear disarmament.
Andrew Futter receives funding from the Economic and Social Research Council. This article reflects the author's views and not those of the ESRC.
Anthony Hopkins does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
Authors: The Conversation