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Fact Check: will renewing Trident cost £100 billion?

The Trident-class nuclear submarine Vanguard. The Scottish National Party want the weapons system to be scrapped. PA/PA Wire

In total, renewing Trident will cost around £100 billion, at 2012 prices, over the next 35 years … It will take up almost a tenth of the UK’s annual defence budget – and around a quarter of the capital budget for the period from 2018 to 2030.

Nicola Sturgeon, Scotland’s first minister, at a talk at the London School of Economics.

Given Nicola Sturgeon and her Scottish National Party’s policy against “renewing the Trident nuclear missile system on principle” – currently based at HM Naval Base Clyde some 25 miles from Glasgow – it is worth investigating the accuracy of the first minister’s statements.

It should be made clear that the term Trident is often used as a shorthand for what is the entirety of the UK’s nuclear forces. Trident, strictly speaking, is only the missile delivery system of a deterrent that consists of three interconnected parts. According to a recent research briefing by the House of Commons:

The nuclear deterrent system is composed of three parts: nuclear warheads which are mounted on Trident II D5 ballistic missiles which are launched from Vanguard-class nuclear powered submarines.

We can distinguish between the more limited cost of the “successor programme” for the current nuclear deterrent (which the House of Commons report estimates at £17.5bn to £23.4bn for the overall programme, including £12.9 to £16.4bn for the submarines) and any estimates for the total costs of procurement and the running costs of the replacement deterrent “over its lifetime”. The “Main Gate” decision on renewing the Vanguard-class submarines is scheduled for sometime in 2016 and full operational service would occur between 2028 and 2035.

The first minister has, by her own admission, based her figures on a report released by The Trident Commission in 2014. By offering a £100 billion estimate it is clear that she is alluding to the latter of the two means of calculating the expenditures: the replacement and total lifetime cost and not just the cost of replacing the three components of the deterrent alone. The figures she offered were calculated with estimates taken from the report.

The Background Paper to the Trident Commission Report states that, the “Net Present Value of this total spend from 2012 to 2060 (capital alongside running costs after 2028 for the new system)… comes to £57.6 billion”.

Sturgeon has arrived at the figure of around £100 billion by multiplying the estimated annual cost of £2.9 billion in 2012 figures that is set out in the report, by 35 years. Why 35 years – taking us to 2050 – is more of a mystery, as the Trident Commission report projects out until 2062, as the graph below shows.

Trident Commission Final Report

These amounts are all “ball park” figures, “illustrative estimates” and projections based on 2012 prices from what open source data is available. They cannot, therefore, be expected to remain fixed especially given inflationary trends in defence procurement.

In recent years, there have been a series of differing estimates offered for the total lifetime expense to the like-for-like replacement deterrent as well as series of estimations for Trident Alternatives. In 2006, the Liberal Democrats suggested that “the true cost of replacing and operating the Trident nuclear missile system would be at least £76 billion” while Greenpeace came to a figure of £97 billion. The recent House of Commons report also refers to the £100 billion estimate but it credits the Campaign for Nuclear Disarmament for arriving at this sum.

In the process of researching these estimates, analysts at the Royal United Services Institute (RUSI) confirmed to me that Nicola Sturgeon’s numbers were “roughly accurate”. Furthermore, a 2013 report released by RUSI, Towards the UK’s Nuclear Century, indicates the successor replacement cost to be at “between £19 billion and £25 billion at 2012-13 prices” but cautioned that estimates for the existing successor programme are “provisional” until the scheduled 2016 “Main Gate” decision on investment transpires. This report also concurs with Sturgeon’s claim that the deterrent will consume 10% the UK’s annual defence budget. It states:

If defence spending remains constant in real terms after 2015-16, spending on the nuclear force could rise to approximately 10% of the defence budget by around 2022-2023, peaking at around 12% by the middle of the decade, and then not falling below 10% until the successor submarine production draws to a close in the first half of the 2030s.


Nicola Sturgeon’s estimate for the total cost of renewing the nuclear force is generally accurate. This estimate is based on the Trident Commission’s report figures of a £2.9 billion average annual cost (in 2012 figures) and an average of 9.4% of the total defence budget annually. If one takes the £2.9 billion annual cost and multiplies this by 35 years you reach a figure of £101.5 billion.

But it should be understood that besides mere replacement, this figure includes the procurement of submarines, the total cost of a missile extension programme, in-service costs and replacement warheads as well as decommissioning costs. It should also be noted that these are all just ball park assessments and that, as the Trident Commission report states, these figures are only “illustrative estimates”. That said, the tremendous cost of retaining a first tier nuclear deterrent combined with the recent trend in declining defence budgets suggests that a real impact on existing and future conventional capabilities is tangible.


The judgement that Nicola Sturgeon’s numbers were generally accurate seems appropriate. It should be recognised that there can be no facts in this area, since we have no idea what renewing Trident will cost, and there are no official estimates. However, this fact check draws on serious estimates, particularly by the independent cross-party Trident Commission 2014 report, run by BASIC and the 2013 RUSI report.

The author is also very clear on what the £100 billion estimate covers. This is both the capital costs associated with the replacement and the subsequent lifetime running costs for the three elements nuclear warheads, missiles and submarines.

The Conversation is fact checking political statements in the lead-up to the May UK general election. Statements are checked by an academic with expertise in the area. A second academic expert reviews an anonymous copy of the article.

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