UK's nuclear future: Beyond Trident

Vanguard-class SSBN - one of the UK's four current SSBNs

Part 2 of 3

In which we look at the options..


Current Position

Today, somewhere at sea, one of four Royal Navy Vanguard class nuclear powered ballistic missile submarines (SSBNs in Navy-speak) is currently busy avoiding detection, carrying 48 warheads on 12 Trident II D-5 SLBMs. Having at least one UK SSBN at sea ready to fire has been maintained since 1968, so-called Continuous At-Sea Deterrence (CASD), a very proud record for the RN. Indeed, mathematically the RN required 5 SSBNs to achieve CASD, so achieving this with four SSBNs for more than 40 years is from a technical and operational perspective very commendable - well done them.

The British submarine's 48 warheads are independently targetable, which makes an SSBNs nuclear payload both highly survivable and enormously destructive. As detailed in SDSR, the UK's warhead stockpile will decline from 225 warheads today to no more than 180 by mid-2020s, and the total number deployed at any one time will decline to 40 warheads on 8 missiles. The UK claims that this is in line with the UK's commitments under the Nuclear Non-Proliferation Treaty (NNPT).

The Vanguard class entered service in the early 1990s, and were designed for a 25-year life. Given a nine-year life extension programme as currently anticipated, the submarines will need replacement from 2028. Building nuclear submarines is a complicated business, meaning that the UK needs to make a decision no later than late 2015; helpfully, this is immediately after the next election (May 2015), which allows the Conservative Lib-Dem coalition to avoid a divisive decision on the future of the UK nuclear weapons programme; the Tories want a like-for-like replacement of Trident, and the Lib-Dems do not, but what the Lib-Dems do advocate is not entirely clear. Some, like the out-going Labour Government want to reduce the SSBN fleet to 3, making CASD probably impossible to maintain, others favour a cheaper cruise missile on existing attack submarines (SSNs) or aircraft, and yet others advocate getting out of the nuclear weapons game altogether. I'll use the NAO's 2008 Trident Replacement study and the House of Commons library's papers for the policy and the numbers.

What, then, are the UK's options? Fear not, we'll return to the UK's needs in part 3.

UK Options
Ignoring impossibly expensive options, like building a full nuclear triad of land and submarine based missiles and manned bombers, there are five main options. First, like-for-like replacement of Trident, maintaining CASD. Second, limited Trident replacement not including CASD. Third, nuclear tipped cruise missiles either from attack submarines or from aircraft. Fourth, air dropped bombs. Fifth, no fielded capability, but with a breakout capability whereby the UK could have a an air-dropped bomb in 12 - 24 months.

(No, not no to cruise. No to nuclear cruise - conventional cruise is much too useful to be jeopardised).

We can reject the third option immediately - nuclear armed cruise missiles. This is because the UK's existing cruise missiles - Tomahawk from submarines and Storm Shadow from Tornado aircraft - are useful in their different roles, and though each were designed to have an optional nuclear payload, it would be extremely dangerous to have both conventional and nuclear tipped versions of the same cruise missiles.

Why?

Simple: if you're on the receiving end of a cruise missile attack, and you cannot tell whether the missiles are conventionally or nuclear armed, then the incentive is to assume you're about to get nuked and therefore fire your nuclear missiles off. This is called the "signalling problem" and actually makes the world materially less stable. Consequently, the UK should not invest in nuclear cruise missiles for as long as it has conventionally armed cruise missiles. And it will for a long while as conventional cruise missiles are very useful.

Option One: Like for Like Replacement, maintaining CASD
Replacement - with four SSBNs and 12 - 16 missile tubes, each containing an upgraded Trident II missile, and mounting four independently targeted warheads. These could be based at Faslane as now, or to save some money, move them to Devonport, Plymouth or Portsmouth, closing HM Naval Base Clyde, Faslane. Likely bill - £20bn for the submarines, £100bn or so over 30 years for the whole system to 2045.

Option Two: Smaller replacement, breaking CASD
It is suggested that the UK could make do with three - or possibly only two - SSBNs, by electing not to have CASD. This would see SSBNs in port or at sea for training, and sortied for deterrent patrols at a time of heightened tensions. The level of savings is unclear, and it provides no guaranteed survivability against a first strike. This option also has signalling problems as the fact that an SSBN was put to sea in a time of tension could be interpreted as a major escalation.


Option Four: Free Fall Air Dropped Bombs
A return to Britain's starting point in the nuclear weapons arena, this option would see the RAF - and possibly the Royal Navy's Fleet Air Arm (FAA) off the carriers in future - using manned aircraft dropping free-fall nuclear bombs. In the short to medium term this would from Tornado strike aircraft or from multirole Typhoons, and in the longer term the Joint Strike Fighter. This would be considerably cheaper than the SSBN option as it would be an additional role for existing aircraft used primarily in other roles, but would be much less survivable from a surprise first strike, could require forward basing rights to strike targets at intercontinental ranges, and compared to an SLBM, aircraft are significantly easier to attack en route to target.

Option Five: Exit the nuclear club
If the UK does not need to have nuclear weapons, then it would be considerably cheaper to exit the nuclear club and retain a breakout capability at Aldermaston. This would mean the ability to fabricate existing designs on air-dropped nuclear weapons with 24 months notice, and in the meantime the scientists and technicians could be put to work in disarmament verification and cooperative threat reduction.

So, some options. In part 3, we'll look at the UK's needs and make recommendations.