Jeffrey LewisBritain’s Independent Deterent 2

After a visit to Aldermaston a few years ago, I noted that “no, the United Kingdom does not in any way, shape, or form have an independent nuclear deterrent.”

In 2009, then-UK PM Gordon Brown announced the UK would be willing to consider reducing the number of Trident submarines from four to three.

This came as a surprise to HMG (Her Majesty’s Government), according to a leaked cable from the US Embassy in London, which contained this helpful explanatory note: “The UK Trident system consists of 160 operational nuclear warheads carried by Trident II (D5) ballistic missiles aboard four Vanguard-class nuclear powered ballistic missile submarines. The warheads and submarines are British built, but with substantial American design assistance.”

Emphasis mine.

Update | 9:00 11 December 2010 That phrase appears in two cables, one from 24 July 2009 and another from 24 September 2009.  It is, it appears, boilerplate.  (The links are to the full text of the cables.)


  1. Charles (History)

    Not to nit-pick, but don’t you mean ‘the UK would be willing to consider reducing the number of Trident submarines from FOUR to THREE’?

    • Jeffrey (History)

      Damn. I’ve fixed the error. Thank you for pointing it out.

  2. FSB (History)

    Well, what does “British built” really mean? Assembled in the UK with US parts and US specs? Jolly good old chap. Carry on. Pass the Marmite….

    • kme (History)

      Just like an IKEA table.

    • John B. Sheldon (History)

      As a Brit, I have to say … Marmite? Really? Dick Van Dyk eat your Mockney heart out.

  3. NER (History)

    Both Brown and the current coalition government have said they will reduce from 4 to 3 SSBNs AFTER the current Vanguard-class retires in the late 2020s/early 2030s if, and only if, the new ‘Successor’ submarine design and reactor enable ‘continuous-at-sea deterrence’ as currently practiced (i.e. 1 from 4 or 1 from 3 subs is always at sea on operational patrol 24/7). This is another case of advancing technology enabling the same nuclear posture with fewer assets being presented today as a ‘responsible’ disarmament measure that MIGHT be realised decades hence.

  4. Andreas Persbo (History)

    It’s not really a one way street. John Walker’s new book on British Nuclear Weapons and the Test Ban: 1954-1973 makes relatively clear, it’s been a two-way communication since the first day of the MDA. Who benefitted the most is something for historians to sort out.

    • FSB (History)

      Nevertheless, the UK does not have an independently-designed nuclear deterrent, nor is it all made in the UK. Recent heavy-lifting has been done by the US. Some UK crumpets and jam may have been involved at tea-time.

      The nukes are the same.

  5. Seb (History)

    Surely the pertinent questions are:

    1. Shot term: does it go bang if someone in the British chain of command presses the button?

    2. Medium term: If the US stops co-operation can the capability (where it is lacking) to maintain the missiles and warheads exist for long enough a period that if the use of required facilities are withdrawn the deterrent can be maintained?

    3. Long term: does the UK maintain a wide enough industrial and scientific base to build new weapons and platforms, if not can it find other partners who can?

    Point 1 is supposed to be pretty much guaranteed. And absent of some confirmation otherwise, it does the trick for deterrent purposes. In any instance where the UK would be willing to use a nuke, it’s not going to be worried about withdrawal of US co-operation in future as there probably isn’t going to be a future.

    Points two and three are only really relevant if the US decides to withdraw co-operation prior to some serious move towards global zero. This would be diplomatically “interesting”, as currently the UK seems to be re-assuring the US that we are not planning to unilaterally disarm. Perhaps the US values the money the UK spends on buying all that kit, and the leverage it perceives it gains in other aspects of the relationship? Where such a move would leave things like ABM radars and base leases, I don’t know. The other alternative is Britain wanting to hold out after some end stage discussion on reaching global zero, that seems equally unlikely.

    But in the interests of completeness Point 2 and 3: well, if the French can do it then the UK can do it if it wants to stump up the resources. Probably with the French if the US ever decided to stop co-operation. The weak point would probably be the delivery systems, needing either new subs or new missiles to be built on a time-scale related to how long tridents remain reliable with whatever maintenance the UK can scrape together.

    The whole argument of whether the UK currently maintains an entirely independent programme or one independent enough to do the job required seems rather sterile.

    If the French had drawn the same conclusions after Suez that the UK drew (no independent foreign policy contrary to your main economic partners interests is possible when the difference in relative strength is so great) then it is likely they might well have pursued the same option the UK did, cutting the costs of maintaining the ability to launch a retaliatory strike to the lowest level in exchange for losing some degree of foreign policy leverage.

    The only possible benefit would be if the UK decided it wanted to try and run a more independent foreign policy that diverged from US interests. This seems unlikely to be a realistic outside a very deep partnership with France and other European powers, in which case, switch American co-operation for French co-operation in nuclear matters to keep cost low, or if it is really worth it, build the capability. Surely nobody is actually suggesting that the UK lacks the engineering and scientific base to be able to build these capabilities at all if the motivation was there?

  6. John Schilling (History)

    Seb has the right questions. The answers, I believe, are:

    1. Almost certainly yes

    2. Almost certainly no

    3. Yes, but it wold be expensive

    Trident missiles require maintenance, which the British cannot do themselves. In some cases, e.g. large solid rocket motor replacement, the necessary industrial base does not exist in the United Kingdom. In other cases, e.g. guidance electronics, the facilities might exist but the specific technical knowledge does not. Even if the British have a complete set of technical manuals, they don’t have the technicians who through hard-earned experience know all the details that didn’t make it into the manuals – and I doubt they have all the manuals.

    If the United States pulls out of the deal, Britain’s missiles will stop working in a few years. It is unlikely that the British could field a credible replacement delivery system on that time scale. They probably could turn Trident warheads into gravity bombs, but the RAF can’t really do deep strike against modern air defenses without outside help any more, so that’s not a credible deterrent.

    Given a decade, maybe even just half a decade with a national-emergency budget to work with, the British could develop a truly independent and credible deterrent. Possibly a domestic Trident-refurbishment shop, more likely something new. That still leaves a few uncomfortably vulnerable years, if both their existing deterrent and their strongest military alliance are falling apart. Most likely, they’d be looking for new allies – and the place to look, in that regard, is just a few miles south.

  7. Seb (History)


    I assume we would convert W76 for delivery by Storm Shadow rather than gravity bombs. The diameter and weights make that look reasonable as a possibility, though I am no expert. It would probably would make sense to buy the French naval long range version, though there would be the issue of needed to modify subs accordingly. I doubt this would take long.

    Certainly, not as reliable as a Trident, but far more of a threat than a gravity bomb, and something that there is occasional debate about doing as an alternative to an expensive new Trident system anyway.

    The US suddenly pulling out could find equal problems in it’s own deterrent through loss of radar stations etc. and the dreaded possibility of technology finding it’s way into the hands of the French. It all seems rather unlikely. The more credible problem likely to arise in the arrangement is the UK deciding to kill Trident unilaterally, which is what these cables are all about. It implies a budget hole in the US that needs to be filled somewhere.

    Joking about crumpets misses the point entirely: the crumpet munching occurred in 1956 when it became clear that the kind of independence of policy that would require a fully independent nuclear infrastructure was not possible for economic reasons, so why re-invent the wheel if there are other options?

    Given the manner in which the US demonstrated this important principle of only having independence in as far as it is economically possible to act independently, it’s the US that should be worried about all those Chinese held T bonds.

  8. George William Herbert (History)

    The French M45 MIRV SLBM isn’t quite a Trident II – the newer M51 is pretty much a TII functional match but too big for the TII tubes – but would fit in the Vanguard tubes and is plenty long ranged for deterrence against all the likely candidates other than China, launched from the North Sea.

    Italy also makes large solids now.

    If the UK turned against the US *and* all of Europe, they’d be in trouble… but they just don’t seem likely to go rogue, as a nation.

    • Corentin (History)

      The M-51 could reach China from North Sea patrol zones if the missile is not loaded with the maximum number of warheads.

  9. Seb (History)

    Sorry for another post… thinking about this has me wondering if buying French missiles rather than Tridents would be that more expensive?

    Perhaps it would make more sense to buy French for the strategic side (UK contribution to the Force de Frappe is probably proportionately more valuable France than UK leasing Tridents is to the US) and bargain harder on base rents on Ascension and Diego Garcia that really are important to the US.

  10. rwendland (History)

    “In 2009, then-UK PM Gordon Brown announced the UK would be willing to consider reducing the number of Trident submarines from four to three.”

    Jeffrey, I think you have misunderstood the cable.

    The announcement to consider reducing the number of Trident submarines to three was made in the 2006 Trident replacement White Paper. (see quotes below) Gordon Brown in 2009 was merely restating that, and indicating that the decision for three or four had still not been made by HMG.

    The cable centres on the delay in making the next decision on Trident replacement from September 2009 until after the NPT Review Conference – i.e. after the 2010 general election. (Now further delayed by the new govt until after the next election.)

    Maybe some in MOD/FCO (and the submarine building lobby) thought that the three or four decision highlighted in 2006 had been made internally at a technical level, and were upset that the PM had decided not to announce that as HMG policy in 2009. Maybe also some press spinners were trying to make Gordon Brown appear to be saying something new. But in reality he was not changing HMG policy, merely restating the 2006 position as unchanged.

    Here are some quotes from the 2006 Trident replacement White Paper.

    “We will investigate fully whether there is scope to make sufficiently radical changes to the design of the new submarines, and their operating, manning, training and support arrangements, to enable us to maintain these continuous deterrent patrols with a fleet of only three submarines. A final decision on whether we require three or four submarines will be taken when we know more about their detailed design.” (intro on page 7)

    5.7 to 5.9 (page 26) has more detail:

    “Three submarines normally are required to be operationally available in order to sustain continuous deterrent patrols, although continuous deterrence can be maintained for limited periods when only two are available. … We will investigate fully whether there is scope to make sufficiently radical changes to the design of the new SSBNs, and their operating, manning, training and support arrangements, to enable us to maintain continuous deterrent patrols with a fleet of only three submarines. A final decision on the number of submarines that will be procured will be made when we know more about their detailed design.”

  11. rwendland (History)

    On the Trident warhead development/production side, assistance from the U.S. was beyond “design assistance”. A significant amount of the “special materials” (Pu) for the UK Trident warheads was supplied by the U.S.

    A 1987 National Audit Office report says:

    “NAO’s examination showed that consideration was given to the purchase of special materials from the US on cost grounds. In 1982 Ministers decided after taking account of the possible options for procurement, together with political, economic and employment considerations, that a substantial proportion should be purchased in the UK.”

    As only a “substantial proportion” was from the UK, the rest must have been cheaper U.S. sourced special materials.

    Source is Appendix 4.4 of:

    Ministry of Defence and Property Services Agency: Control and Management of the Trident Programme. National Audit Office. 29 June 1987. ISBN 0102027889 [not available online]

  12. bob (History)

    It seems unlikely that the “special materials” were Pu – the UK has shedloads of the stuff – I think it more likely to be boost gas and/or fogbank related. That said, there are other components that could fall under the catch-all “special materials”.

    Regarding the timeframe of the NAO report – I undertand that Thatcher ‘gave’ approx 20 metric tons of Pu to the US and that the US ‘gave’ the UK some tritium and fabricated components. Comparative advantage possibly?

    • rwendland (History)

      Bob, I’m pretty sure it was Pu the NAO was referring to for several reasons:
      a) previous para defines it “special (ie fissile) materials”
      b) previous para says this is the largest UK warhead expenditure area, so this is not a small component
      c) following para say BNFL is the UK supplier – almost certainly Sellafield plutonium facilities

      Remember AWRE had fairly recently been making WE.177C and Chevaline warheads, and had serious problems with its Plutonium Processing Building following the critical 1978 Pocbin report (mentioned as a Trident problem in the NAO report). It could easily have run down usable weapons plutonium stock. The shedloads of Pu was reactor grade from the civil programme.

      Although the NAO talks about purchasing the special materials from the U.S., I suspect it is the transfers of 0.47 tonnes Pu to and from the U.S. documented in the 2001 MOD “Plutonium and Aldermaston – An Historical Account” document as “These transfers remain classified”. I suspect the U.S. essentially lent us Pu for the Trident warheads, which we later replaced from other/new stock.

      That document also lists the UK Pu for US Tritium and HEU barters under the MDA:

  13. Martin Butcher (History)

    As much as anything this cable was about the changing style of British government and the centralisation of power in the Prime Minister’s office. The PM used his own advisors to decide and announce a policy line without consulting the FCO or the MoD. They weren’t happy and let the US Embassy know that through the briefings reflected in the cable. It’s a continuation of a trend that began with Margaret Thatcher, but really accelerated under Tony Blair.

  14. rwendland (History)


    The NAO report I mentioned above actually enumerates the amount of “Substantial American assistance”, because it breaks down costs between US and UK spending on a per toplevel subsystem basis. Using the latest cost estimates the NAO then had (1986/87 I think), the US% of spending was:

    Item US£m UK£m Total£m US%

    Submarines 313 2536 2849 11%

    SWS_Equipment 1029 144 1173 88%

    SWS_Missiles 1056 14 1070 99%

    Tactical_Weapon_System 2 726 728 0%

    Shore_Construction 0 671 671 0%

    Warhead+misc+unallocated_contingency 1078 1696 2774 39%

    Total 3479 5786 9265 38%

    SWS = Strategic_Weapon_System (i.e. Trident)

    I’m dubious that the above costs include the costs of established staff at AWRE and MOD on the project, so may well underestimate UK costs, which would lower the real US% somewhat. But the above is a reasonable ballpark.

    In the 1981 cost estimate, US spending was higher at 44% in total, but UK costs increased (partly inflation) reducing US%. The $/£ rate also substantially declined 1981 to 1987 saving UK on US costs; without that good fortune US% may have stayed nearer that 44%.

    If you particularly want a copy of that NAO report, you can email the NAO and they will email back a scanned PDF. Follow the instructions in:

  15. bradley laing (History)

    How much of the U.S. conventional weapons capacity is dependent on “foriegn” sources? How does one measure how much a given countries military is dependent on “foriegn”
    sources? What if most countires do not have an “independent conventional detterant,” because they are dependent on something they need for conventional forces?