Lib Dems call for end to Trident submarine patrols

BRITAIN should end round-the-clock patrols by the Royal Navy’s nuclear missile submarines and reduce the size of the fleet that has formed the basis of the UK’s ultimate deterrent for the past 45 years, the Liberal Democrats proposed today.

The Lib Dems have opposed a like-for-like replacement of Trident. Picture: Getty
The Lib Dems have opposed a like-for-like replacement of Trident. Picture: Getty

Danny Alexander, Chief Secretary to the Treasury, said Britain could maintain a credible nuclear deterrent while downgrading the replacement of its four-strong Trident submarine fleet.

He made the claims after the publication of a Lib Dem defence review, which concluded there were alternatives to the UK’s current nuclear stance, which requires at least one nuclear-armed submarine to be constantly at sea. The Lib Dem MP’s proposal that the continuous at-sea deterrent could be cut and the nuclear fleet reduced by one or even two submarines, put his party at odds with its Conservative coalition partners, who believe the deterrent should stay as it is.

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With the existence of Trident in Scottish waters already a defining issue of the independence referendum, the SNP dismissed the review as a “joke”, arguing that a Yes vote was the only way to rid the Faslane base on the Clyde of nuclear weapons.

The review, led by Mr Alexander, was launched by the Prime Minister David Cameron and his deputy, Nick Clegg, as part of the coalition agreement and in recognition of the Lib Dem opposition to like-for-like Trident replacement.

Mr Alexander appeared to accept that the Trident Alternatives Review effectively ruled out developing a cheaper alternative to the Trident ballistic missile – such as a system based on cruise missiles.

Although the Lib Dems had wanted a cheaper alternative to Trident, Mr Alexander conceded there was no system available that could be introduced in time for the end of the lives of the Vanguard submarines that currently carry the missile.

“But there is a step down the nuclear ladder still available – ending 24-hour patrols and procuring fewer successor submarines, moving on from an outdated Cold War concept of deterrence to one fit for the world we inhabit,” the Treasury Chief Secretary said.

He said reducing the submarine fleet to three vessels and ending the continuous deterrent would be a major step towards international nuclear disarmament while cutting the estimated £20 billion to £25bn cost of the programme by £4bn.

Mr Alexander’s position opened up a major gap in the defence policy of the coalition partners, which will not be resolved until after the next general election in 2016.

He said: “Trident is the last unreformed bastion of Cold War thinking. Britain in the 21st century needs to think about nuclear deterrence and disarmament in a fresh way.

“We have a big decision to make in 2016, and this study shows there are credible alternatives that don’t compromise our security but do allow us to move on from the Cold War.”

The precise details of Lib Dem nuclear policy – for example whether to reduce the Trident fleet by one or two submarines, will be thrashed out at its party conference this autumn.

Yesterday, Downing Street made it clear that Mr Cameron was committed to the continuous at-sea deterrent.

“He has seen no evidence that there are credible alternatives,” the Prime Minister’s official spokesman said.

That position was supported by Conservative Defence Secretary Philip Hammond, who poured scorn on the LIb Dems’ “part-time deterrent”, warning that the cost savings of reducing the size of the fleet would be far lower than claimed.

“We have had for 45 years now a continuous at-sea deterrent posture, which has served this country very well and we do not believe that, with more countries seeking to get nuclear weapons, this is the time to downgrade, certainly not to go to a part-time deterrent,” Mr Hammond said.

“The part-time deterrent will save us only trivial sums of money, about £50-60 million a year in net present value terms over the life of the system. In the context of the overall defence budget that’s about 0.17 per cent, that’s a tiny saving for a huge gamble with Britain’s security.”

Meanwhile, SNP defence spokesman Angus Robertson responded angrily to the coalition’s internal argument over a weapons system the Nationalists have vowed to remove from Scotland if the country votes for independence.

Mr Robertson said: “The Trident review isn’t worth the paper it’s written on.

“The Westminster establishment seem to have forgotten that Trident is based in Scotland, and neither the people nor parliament of Scotland want it here.

“The review also fails to mention any other possible sites for the weapons – showing disdain for the people of Scotland and ignoring next year’s referendum.”

He added: “This review panders to the vanity of the Westminster system, which wants to keep this out-dated, dangerous arsenal of nuclear weapons on the Clyde.”

The review concluded there were alternatives to Trident being kept at sea for 24 hours a day that would be “capable of inflicting significant damage” to deter potential adversaries.

It did acknowledge, however, that none offered the same degree of resilience as being at sea continuously, “nor could they guarantee a prompt response in all circumstances”.

It acknowledged that ending continuous at-sea deterrence would require a degree of “political confidence” that an aggressor would not launch a pre-emptive attack without notice while the UK did not have a submarine at sea.

Replacements: The options


Large aircraft: Initially, a modified civilian plane or a military stealth bomber were considered. Subsequent analysis showed that attempting to modify a civilian aircraft was likely to be a very high–risk option: such aircraft are designed to hold cargo/passengers safely and are unlikely to be able easily to accommodate the insertion of a bomb bay, let alone the sudden change in centre of gravity when firing missiles.

A stealth bomber was judged to be significantly more expensive and the potential need for and cost of supporting aircraft to defend it would need to be considered should counter–stealth technology develop over the life of the system.

Fast Jet: Joint Strike Fighter (JSF), below and the French Rafale aircraft were considered, but Rafale’s incompatibility with UK aircraft carriers would have been a significant cost driver. Concern was raised about the JSF range and the need for aircraft carriers to get relatively close to target before deploying cruise missiles.


Ships with ballistic missiles or hypersonic glide vehicles were excluded, as the required size of such a vessel and of its escort force was likely to cost as much as submarine–based options, but would be significantly more vulnerable.

The report suggested that it was impractical to have a fleet of nuclear–armed surface vessels sustained across multiple operating areas close to potential adversaries. At the other extreme, holding all the nuclear–armed ships in the UK at very short notice to sail (as is possible for the aircraft options) is also not appropriate, given the ships’ significantly longer transit times.

Deploying vessels irregularly could keep adversaries guessing, but such a pattern would have an effect upon the ability of the wider fleet of ships to enter overseas ports unless they declared that they were not nuclear–armed.


Previous analyses have concluded that the infrastructure and land requirements made a land launch facility option prohibitively expensive, because it assumed that a very large physical footprint was required. To avoid this, an option was modelled based on a smaller physical footprint rather than a very large distributed set of missile silos. This produces a reduced resilience to attack.

A ballistic missile silo, pictured right, is significantly more vulnerable simply because its location will be known by an adversary. This vulnerability, and the risks associated with a “hair–trigger launch posture”, were key factors in the decision not to pursue detailed analysis of the silo option.

The review also looked at a mobile ballistic missile launcher. The option was discounted due to the high technical and cost risk associated with an indigenous development programme, as well as the operational risks associated with protecting, basing and moving such a platform within the UK.


The report compared operating submarines armed with cruise missiles and those carrying ballistic missiles such as Trident, left. Three categories of submarine were considered: hunter–killer (SSNs), which can fire cruise missiles; submarines whose only role is to fire ballistic missiles with nuclear warheads (SSBNs); and a hybrid known as SSGNs – SSBNs modified so they can fire large numbers of cruise missiles, instead of or as well as ballistic missiles.

The report said the highest level of assurance the UK could attain with a single deterrent system was provided by SSBN submarines operating a continuous at–sea deterrence posture. The range of the Trident missile allows the submarine to operate covertly, revealing its position only when it launches a missile. Adopting a non–continuous posture introduces some vulnerability because an adversary can target the UK during a period when no boat is covertly deployed.

Analysis by Tim Ripley: Alternatives have their risks and benefits

If you listen to Defence Secretary Philip Hammond and Liberal Democrat nuclear point man Danny Alexander debating yesterday’s report into the future of the UK’s nuclear deterrent, you may be left wondering if they were discussing the same document.

Both men were able to cherry-pick quotes and statistics to support their apparently opposed views. Hammond was rooting for a like-for-like replacement of the current fleet of four Vanguard submarines and their continuous at-sea patrols, while Alexander pushed for the apparently cheaper option of cutting the fleet to two submarines.

The full report was prepared by a group of MoD civil servants and Royal Navy officers and the declassified summary published yesterday is the first time alternatives to Trident have ever been given any sort of official stamp of approval.

Sustaining Britain’s nuclear deterrent through to 2060 is possible with other systems and force postures, say the anonymous authors of the report, but it will all involve different equipment, costs and risks. The report compares the costs and risks of the current Trident force, going down to two or three Trident-equipped submarines, moving to cruise missiles fired from Astute hunter-killer subs, operating a mix of Astute and Trident missile-firing subs, and moving the deterrent into the air, on the US-made Joint Strike Fighter or to cruise missiles launched from converted transport aircraft.

In its analysis, the report does not discount any of the solutions out of hand. The costs, risks and benefits will just be different from today.

While it clearly says moving away from the current Trident system will cost up to twice as much as over the life of the replacement, the 36 extra Joint Strike Fighters needed for an airborne nuclear deterrent would be able to supplement the rest of the RAF in non-nuclear conflicts. That is a benefit as well as cost. And cutting continuous at-sea patrols to two subs would also provide an effective deterrent – though it increases vulnerability to a pre-emptive strike.

Although none of this analysis is new, it highlights the need for a major policy rethink. The Trident replacement debate is far from over.