All operational scenarios can (thankfully) seem unlikely and fantastical but to those responsible they provide the basis for sizing the force, and endow the deterrent with some credibility.
Diplomatic and Political Implications
Against all these considerations there is the argument that the increase in numbers undermines the UK’s strong backing for the Non-Proliferation Treaty. The Defence Secretary insisted that nothing has changed. He told the Commons that the Attorney General had ruled ‘we do not believe that the changes to the number of warheads in any way breach the nuclear non-proliferation treaty’. There is a long-standing debate about the importance of Article VI of the NPT which looks to the declared nuclear powers ‘to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a Treaty on general and complete disarmament under strict and effective international control.’ The UK move will not help but there are bigger current issues to concern delegates to the next NPT Review conference, notably the end of the INF Treaty and the last-minute reprieve of New Start.
The last question is whether there are major political advantages to sticking to a minimum deterrent posture. The rationale for pushing the numbers as low as possible was made by Tony Blair in 2006:
We already have the smallest stockpile of nuclear warheads among the recognised nuclear weapons States, and are the only one to have reduced to a single deterrent system. In this White Paper we are announcing a further 20 per cent cut in our operationally available warheads. This leaves the deterrent fully functioning, with fewer than 160 warheads, but it means Britain continues to set an example for others to follow in our commitment to work towards a peaceful, fairer and safer world without nuclear weapons. Our decision to maintain the deterrent is fully compatible with all our international legal obligations.
The UK’s nuclear force would account for ‘less than 1% of the global inventory of nuclear weapons’. Its stockpile would be ‘the smallest of those owned by the five nuclear weapon States recognised under the Nuclear Non-Proliferation Treaty (NPT)’.
If this was an example none followed. France, unlike the UK, still maintains air-based systems and deploys more warheads on its SSBNs. Nor has the UK got much credit for its stance. For those opposed to nuclear weapons the only acceptable number for an arsenal is zero. Certainly the latest move has been condemned. David Cullen, the director of the Nuclear Information Service, described the move as ‘highly provocative’, adding ‘If they are tearing up decades of progress in reducing numbers, it will be a slap in the face to the 190 other members of the treaty, and will be regarded as a shocking breach of faith.’
Yet in 2006 when Blair made his case for a minimum deterrent, Cullen’s predecessor at the Nuclear Information Service, Di McDonald, observed that the reductions to date ‘have not been disarmament measures, they have been measures to remove old weapons that have become obsolete and they have been measures of efficiency’. It is instructive to look at other comments gathered by the Select Committee on Defence at the time: Paul Ingram, of BASIC: warhead reductions ‘almost irrelevant because we will still have 48 warheads out on patrol at any time’. Greenpeace: ‘the potential arsenal carried by a Vanguard submarine on patrol remains unchanged despite any wider stockpile changes proposed in the White Paper’. Bruce Kent, of CND: reductions in warhead numbers, though ‘certainly…welcome,’ more likely reflect ‘good housekeeping’. Dr Rebecca Johnson of the Acronym Institute for Disarmament Diplomacy: the new ceiling of 160 warheads ‘may…be little more than a political bid to make a virtue out of necessity’. The Committee stated that: ‘We welcome this arms reduction measure, but it is unclear whether this has significance as a non-proliferation measure. Since the White Paper proposes no changes to the number of warheads deployed on UK submarines, it is unclear that this reduction has any operational significance.’