Jeffrey LewisBritain To Replace Trident

Parliament voted 409-161 to support “the Government’s decisions, as set out in the White Paper The Future of the United Kingdom’s Nuclear Deterrent, to take the steps necessary to maintain the UK’s minimum strategic nuclear deterrent beyond the life of the existing system …”

I confess that I do not fully understand Britain’s system, but the process—laid out in the Ninth Report from the Defence Committee, Session 2006-07—offers other opportunities for intervention:

Suggested Timeline for Future Decisions

Date Decision
2007 Decision in principle to preview new SSBNs and extend life of D5 missile
2007-2009 Initial concept and design work for a new submarine
c 2009-13 (“next Parliament”) Decision on replacement of warhead
2009-2016 Detailed design work on new submarine
2012-14 Contract to be placed for detailed design of new submarine
2016 Contract to be placed for build of first new SSBN
2016-2023 Build programme for first new SSBN
2022 HMS Vanguard out of service (with 5 year life extension)
2024 HMS Victorious out of service (with 5 year life extension)
2024 First new SSBN in service
2026 HMS Vigilant out of service (with 5 year life extension); Second new SSBN in service
2029 HMS Vengeance out of service (with 5 year life extension); Third new SSBN in service
2020s Decision on Trident D5 missile successor
2030-32 Fourth new SSBN (if required) in service
2030s Development of new ballistic missile
early 2040s Life-extended D5 missile out of service
2050s New SSBNs out of service

This decision is not binding on the next Parliament, which will make a decision on replacing the Britain’s warhead and issue a contract for the detailed design of the new submarine.

The Foreign Secretary, Margaret Beckett stated that the Prime Minister confirmed the voted was a “decision of principle … It is inevitable that there will be future discussions, and there will be decisions down the road as the programme proceeds.”

Dick Garwin, Phil Coyle, Ted Postol and Frank Von Hippel argued rather persuasively that this decision did not need to be taken at this time—expressing skepticism that the UK’s Trident submarines “were only designed for a 25-year life” as the UK White Paper stated. “More likely,” Garwin, Coyle, Postol and Von Hippel argued, Trident submarines “have a ‘minimum design life’ of 25 years and are likely to be operable for a much longer time.”

The warhead replacement, by the way, is a really interesting question. Hans Kristensen has posted declassified documents that conclusively demonstrate that Britain’s nuclear warhead design is essentially similar to the US W76 (right).

As I have noted before, the W76 is the warhead slated for replacement by the Reliable Replacement Warhead, closely linking the questions of Trident replacement in Britain and RRW in the US.

I don’t fully understand how these two debates interact, but it seems to me that this is an interaction worth thinking about.

Late Update: Somehow, I missed Peter Scoblic’s brilliant commentary on Trident, observing:

”’What if’ is the essential argument – if it can be called that – for the government’s decision to continue deploying 16 megatons of destructive power in the post-Cold War world, even though Britain’s deterrent does not actually deter.”


  1. Limey

    As I understand it, the issue with the 25 year life span of the submarines is linked to two issues.Firstly, there is the reactors. To allow for a longer life, these would have to be replaced. Unlike with the US submarines, the UK ones were not made with easy access to the reactor compartment – replacing it would mean cutting a large hole in the boat, and through decks, and then repairing that hole.

    The second is the material used for the hull. Due to a number of reasons when they were originally built, the steel used is just not capable of lasting that long at sea. So as well as tearing a big hole to put a new reactor in, a whole new hull would have to be made as well. Once you’ve started getting to that sort of work, it becomes easier and cheaper to build new, more effective submarines.

  2. DAN PLESCH (History)

    you can my my few cents worth on the US-UK interaction, in evidence to the Defence Committee Report cited in the blog; in a paper on Britain’s WMD at This was endorsed by Robin Cook in his last article for the Guardian; and in two cover stories for

  3. Giorgio Franceschini (History)

    Most disturbing about the Trident replacement decision is how the British government sold it to the public: basically Blair said, we have to hedge against the unknown. No specific threat out there, but the future is uncertain. Wow! This is nothing but an implicit invitation to approx 200 non-nuclear weapons countries to acquire nukes. Thanks Tony, what a great legacy.

  4. Jeffrey Lewis


    Thanks for your comment. In the interest of keeping the discussion focused, I should note that Garwin et al address those questions in some detail:

    4. The White Paper on The Future of the United Kingdom’s Nuclear Deterrent submitted to Parliament by the Secretaries of State for Defense and Foreign and Commonwealth Affairs (hereafter Defense/Foreign Affairs, for short) argues, however, that a life extension is not possible for Britain’s Tridents:

    “We have undertaken detailed work to assess the scope for extending the life of those submarines. Our ability to achieve this is limited because some major components on the submarines – including the steam generators, other elements of the nuclear propulsion system and some non-nuclear support systems – were only designed for a 25-year life. The submarines have been, and will continue to be, subjected to a rigorous through-life maintenance regime and we believe that, by revalidating those components, it should be possible to extend the life of the submarines by around five years.”

    Since the UK Tridents are still relatively young, however, it may be that improved management of their water chemistry could drastically extend the steam generator lives. The US has a major R&D program in that area whose results could presumably be shared with the UK. More fundamentally, we are skeptical that the submarines “were only designed for a 25-year life”. More likely, they have a “minimum design life” of 25 years and are likely to be operable for a much longer time. … The lesson for the submarine replacement program is that continued monitoring of the submarines in service may show well in advance that the service life, with proper maintenance and corrective action, can much exceed the 25-year minimum.


    18. That UK Government White Paper does not cite metal fatigue and hull corrosion as life-limiting factors for the UK Trident submarines. It simply indicates that (pp. 9,10)

    “… some major components of the submarines—including the steam generators, other elements of the nuclear propulsion system and some nonnuclear support systems—were only designed for a 25-year life…There have been some suggestions that we should replicate US plans to extend the lives of their Ohio-class SSBNs from 30 to over 40 years. A substantial life extension of this kind would need to have been built into the original design of the Vanguard Class and into the subsequent manufacture, refit and maintenance of the boats. Unlike with the Ohio class this was not the case.”

    In systems designed conservatively to ensure a minimum life of 25 years, it is common to find from experience that the system or component can be operated safely for a much longer time; often it is the advent of smaller, cheaper options that cause the scrapping of equipment, as is certainly the case with computers. Here, however, the replacement would carry the same large missiles and fulfill the same mission, so that the benefits of newer technology are minimal—or at least unstated in the White Paper. Certainly, a much more detailed consideration of the options than is offered in the Defense/Foreign Affairs White Paper would be required to make a judgment between a life-extension program and a program for building new submarines.

    19. In our experience, until these matters are properly prepared for outside review, they are not adequately formulated for inside decision makers. We see no reason why questions such as the possibilities for control of the corrosion of steam generators cannot be fully discussed in public. As for the “other elements of the nuclear propulsion system and some non-nuclear support systems … only designed for a 25-year life” not otherwise detailed in the White Paper, these are surely replaceable in case surveillance shows the need to do so, and it is only a matter of cost-to-replace compared with the proposed program for replacement of the fleet itself.

  5. Limey

    Regarding the arguments on longevity, the House of Commons Defence Select Committee report is interesting:

  6. M (History)

    All this and it looks like the Russians will go to any length to not destroy their SSBNs. This is near their SSBN burnout stands.

  7. Jeffrey Lewis

    The MOD’s arguments are laid out in written evidence presented to the House of Commons:

    Some details on those components of the Vanguard-class submarines, which we believe are critical in terms of limiting the effective service life of the submarines, are set out at paragraph 1-3 of the recent White Paper. Life extension much beyond five years is likely to require replacement of some of the systems critical to submarine operations, such as external hydraulic systems, elements of the control systems (plane and rudder), sonar systems, electrical systems (including main battery) and refurbishment or replacement of elements of the nuclear propulsion system. This would involve some hull penetrations. Replacing these systems would require extended additional maintenance periods resulting in loss of boat availability and significant cost but would not enable significantly increased life. Extension to both component safety justifications and the whole reactor plant safety justification would also be required (and could not be assured). Other systems would need careful assessment and replacement of the turbo generators, secondary propulsion gear and assemblies, deterrent missile hydraulics, hatches and mechanisms, might be required. There would also be increasing risks with the reliability of other major systems, including potentially the main engine, gearbox shafting and propulsor, all of which could require replacement.

    As was made clear in the White Paper, we do not at this stage completely rule out further life extension of the Vanguard-class. The key point is that on current evidence it is highly likely to represent poor value for money. Moreover, there is also serious concern as to whether it will be technically feasible. The position will be kept under review at each key stage of the programme to design and build the replacement submarines. But given the severe uncertainties associated with life extension beyond the 30-year point, it would be grossly irresponsible not to start concept and assessment work in time to ensure we can field replacement submarines when the Vanguard-class reaches the 30-year point.

    In this context, we would like to reiterate two points to the Committee. First, we believe the most relevant comparison with the Vanguard class—in terms of likely in-service life—is our own classes of submarine and not the US Ohio-class, to which some commentators have referred. The Ohio-class submarines are different boats with different original design life and a different manufacture, refit and maintenance regime, as made clear in paragraph 1-4 of the White Paper. The Resolution class submarines, for example, were maintained in-service for from 25 to 28 years and experienced serious loss of availability and significantly increased maintenance costs towards the end of their lives. We have no wish to repeat that experience.

    Second, many commentators have contrasted the 17 years quoted in the White Paper to design build and commission a new class of SSBNs with the time between the decision to procure Trident in 1980 and HMS Vanguard’s first patrol in 1994. This overlooks the point made clear in the White Paper that much of the concept and assessment work for the Vanguard-class submarines, the stages on which we are about to embark for the replacement SSBNs, was carried out in secret in the decade before the decision to procure Trident was taken in 1980. Again, we do not believe that it would have been responsible or acceptable to have followed a similar course on this occasion.

  8. Rwendland (History)

    It is remarkable that the White Paper did not properly consider the cheaper replacement options of nuclear-armed cruise missiles launched from existing multi-purpose platforms (SSNs/surface-ships/aircraft), or the option of life-extending the existing SSBNs as non nuclear-powered anchored or limited mobility launch platforms. Instead the options considered (set up to fail?) were a gold-plated cruise-missile solution using 20 new converted civil aircraft + 2 airfields (one entirely new) + new refueling aircraft, or a new land-based silo system, both of which come out as twice as expensive as replacement of SSBNs. (Or a new stealth surface ship + defence/support ship option at the same cost as SSBNs.)

    Fixing the facts around the policy?

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