The Liberal Democrats manifesto has made an incorrect point regarding the patrolling patterns of Trident carrying submarines.
This article is part of a series looking at the manifesto claims made by the main parties in the run up to the 2019 General Election.
The Claim: “Maintain a minimum nuclear deterrent, while pursuing multilateral nuclear disarmament: continuing with the Dreadnought programme, the submarinebased replacement for Vanguard, but procuring three boats and moving to a medium-readiness responsive posture and maintaining the deterrent through measures such as unpredictable and irregular patrolling patterns.”
The Reality: The idea of building three submarines instead of four – the minimum number needed to maintain a continuous at-sea deterrent – would mean that patrols are in fact more predictable as there will be long periods in which submarines are not ready to sail. The UK operates four submarines in this role to ensure that one is always available to sail while the others are in refit, working up for deployment and having just come off patrol.
Verdict: Reducing the fleet from four to three boats would not result in anything beyond negligible cost savings for what would be a significant decrease in availability. It is not correct to say that it’s possible to maintain unpredictable patrolling patterns with only three submarines as foreign states would be fully aware of when submarines are in maintenance or haven’t deployed.
What’s the background here?
The Liberal Democrats have often argued that, post-cold war, a four-submarine nuclear fleet is no longer necessary. However analysts argue that four submarines are needed to maintain ‘continuous at-sea deterrence’ – an approach which allows the UK to keep one of the submarines at on patrol at all times, with enough back-up to switch submarines as needed and cover unexpected eventualities.
The UK has already reduced the overall explosive power of its nuclear arsenal by 75% since the cold war. It is also believed that savings to the Ministry of Defence budget might be £3bn to £5bn, and even more in reduced running costs. However, the claim above is that it’s possible to “maintaining the deterrent through measures such as unpredictable and irregular patrolling patterns” and with three boats, that’s not possible.