Scottish independence: Where might Trident go?

Map of where Trident could end up

Scottish ministers say the UK's nuclear deterrent - the submarine-based Trident - will be banished from Scotland if it becomes independent. The UK government says there are no plans to move it. But where could it relocate to if it had to?

The UK's nuclear weapons system - currently made up of four Vanguard-class submarines which carry Trident strategic missiles - has been based at HM Naval Base Clyde on Scotland's west coast since the 1960s.

The site is made up of two main parts - Faslane on the Gareloch, where the submarines are based, and Coulport on Loch Long, eight miles away, where the warheads are stored. The sites are kept separate for safety reasons.

The UK has had at least one submarine on patrol at any given time for more than 40 years and has used the Trident system since the 1990s.

Both Conservatives and Labour want a like-for-like replacement when the existing fleet ends its working life in the late 2020s, while the Liberal Democrats want to downsize to three submarines, saying the existing system was designed for the Cold War era.

The UK government says all Royal Navy submarines will be based at Faslane by 2017 - supporting 8,000 jobs - and there are are no plans to move the nuclear deterrent. Defence Secretary Philip Hammond has said any alternative solution would come at huge cost and take decades.

In 2012, an inquiry into independence by a cross-party group of MPs concluded that identifying and recreating a suitable base to replace Faslane and Coulport would be "highly problematic, very expensive, and fraught with political difficulties".

However, the Scottish government says if Scotland votes "Yes" in the independence referendum on 18 September, Trident will be removed - with the weapons' withdrawal by 2020 - and a written constitution would ban nuclear weapons from being based in Scotland.

It also says Faslane has a "strong future" as a conventional naval base and the joint HQ for defence forces of an independent Scotland, and military personnel employed there would match current numbers.

So if the UK had to relocate Trident, where might it go?

1. Milford Haven
Tanker in Milford Haven dock Milford Haven is home to two liquefied natural gas facilities

In 2012 Wales's Labour First Minister Carwyn Jones said the UK's nuclear-armed submarines and jobs associated with it would be "more than welcome" in Wales if they left Scotland. The remark that was met with an angry response from Plaid Cymru politicians and activists who cited safety risks.

When the original shortlist was drawn up for basing Trident's predecessor Polaris in the 1960s, Milford Haven in Pembrokeshire was one of the candidates.

The Welsh site is an attractive option because it is a natural deep-water port. But In the 1960s Esso had just established an oil refinery in the town and the MoD decided the two were incompatible on safety grounds, according to William Walker, one of the authors of Uncharted Waters: The UK Nuclear Weapons and the Scottish Question.

"The dangers of handling and storing high explosives near major oil facilities ruled it out. Imagine a big submarine colliding with a tanker. It's common sense - even if there is a low probability, the consequences could be horrific," he says.

Nowadays the town's economic and industrial output makes that line of thinking even more tricky. The haven is home to two liquefied natural gas (LNG) facilities and handles 30% of the UK's gas supply. It also hosts two oil refineries and will soon have a new power station.

Dr Nick Ritchie, a lecturer in international security at the University of York, says it's inconceivable that the MoD would allow LNG plants and oil refineries to stay open if Trident was relocated to Milford Haven.

And he says closing the refineries and petrochemical plants would have "a pretty significant economic impact".

Walker thinks there would also be a question over whether the port could take the submarine traffic. There is also the possibility Wales might follow in Scotland's footsteps and call for further devolution or independence. If it voted for that, and took the same stance as Scotland, the MoD would be back to square one.

2. Plymouth
HMS Turbulent at Devonport Trafalgar-class submarine HMS Turbulent at Devonport

Devonport Dockyard in Plymouth - the biggest private-sector employer in Devon and Cornwall - is the main nuclear repair and refuelling facility for the Royal Navy.

It is also home to the Trafalgar-class submarines, which will be moved to Faslane by 2017.

The port's size - the largest naval base in Western Europe covers more than 650 acres and has 15 dry docks, 25 tidal berths and five basins - and familiarity with submarines has led some to believe Devonport might be the best option for an alternative location for Trident.

However, the Royal United Services Institute's Malcolm Chalmers says even though - time and expense allowing - Devonport might work as an alternative to Faslane, it couldn't recreate Coulport.

Coulport possesses a huge floating dock where warheads are placed inside the missiles, 3km from the small village of Garelochhead on one side and the small village of Ardentinny on the other, Westminster's Scottish Affairs Committee heard in 2012. Any new warhead storage facility would need similar distances from population centres for loading and offloading warheads from missiles.

Devonport naval base, Plymouth

The dockyard is also in a densely populated area, which poses a safety risk. There are about 166,000 people living within 5km of the Devonport base, compared with about 5,200 within that distance of Faslane and fewer close to Coulport. The city of Plymouth has about 250,000 residents and is within 3.5km of the dockyard. Glasgow has a population of about 600,000, but it is 25km away from Faslane.

Walker says loading warheads into the missiles on Trident is "very delicate and complicated" and a process that shouldn't be done in or near built-up areas.

"You can't have Trident missile bodies laden with rocket fuel and nuclear warheads near a city of quarter a million people - the UK regulatory authorities would be very uncomfortable with that," says Ritchie.

Lifting missiles is also a safety risk. "There needs to be an explosive handling jetty that is designed for the worst case scenario - if a missile is dropped or there is an earthquake, even if this might only happen once in several thousand years, and high explosives are scattered," says Chalmers.

Trident facts and figures
HMS Victorious
  • UK has four Vanguard Class submarines: HMS Vanguard, HMS Victorious, HMS Vigilant, and HMS Vengeance
  • They were launched between 1992 and 1998
  • Vanguard-class vessels are 150m (492ft) long
  • Ministry of Defence estimates cost of replacing all four submarines at £20bn
  • Submarines are based at Faslane on Gareloch
  • Missiles are kept at Coulport on Loch Long
  • UK has access to 70 Trident missiles held in communal pool at strategic weapons facility in Georgia, USA
  • Trident missile system replaced the Polaris system

In 1963, Falmouth was suggested as a warhead depot option - like Coulport - in combination with Devonport. However the MoD dismissed the idea because it wanted the ammunitions depot to be within one hour's sailing of the submarine base. Falmouth is 70km west of Devonport. However Chalmers thinks this combination could be a runner. "But it would require substantial political will," he says.

Falmouth was also seriously considered in its own right in the 1963 shortlist. However, the area has a strong tourist economy and the proposed site would have required National Trust land acquisition which would be very difficult, if not impossible.

Olympic games 2012 Weymouth hosted the sailing events in the 2012 Olympics

Portland, Weymouth, was the third English port to make the shortlist. It was ruled out because it didn't have a close enough site for the warheads depot. Chalmers says it was the issue of warhead loading being kept far enough away from people and sites of economic value that meant Scottish locations made six of the 10 shortlisted 1960s options.

Portland's naval base and the neighbouring Naval Air Station have now been closed down and replaced by a residential and commercial marina which hosted the sailing events in the 2012 Olympics.

3. Barrow-in-Furness
The BAE Systems construction hall dominates the skyline above the town of Barrow-in-Furness, The Vanguard submarines were built in Barrow-in-Furness

An existing nuclear site that could be considered is Barrow-in-Furness in Cumbria, where BAE are currently building the nuclear-powered Astute-class submarines.

However, the base didn't make it on to the 1963 shortlist because Walney Channel is thought to be too shallow for nuclear submarines.

Part of the problem is tidal. There are only a certain number of hours in each month when the tide is high enough for nuclear submarines to transit into the open sea, a 2005 investigation by research group RAND found.

Even at these restricted times the vessel has to travel fast to complete the journey.

Trident II D5 missiles
  • Length: 44ft (13m)
  • Weight: 130,000lb (58,500kg)
  • Diameter: 6ft 11in (2.11m)
  • Range: 7,500 miles (12,000km)

The problem isn't just theoretical. The second Polaris submarine to be built at Barrow, HMS Repulse, ran aground when it was launched in November 1967.

However, Francis Tusa, editor of Defence Analysis, told the 2012 inquiry by a cross-party committee of MPs that Barrow's advantage was that it already had support facilities, including a ship-lift, similar to Faslane.

Substantial dredging would also make the site more accessible.

There are other problems though. The size of the current dock means it would not have room for more than two Vanguard-class submarines and the town - which has a population of about 69,000 - is close by. There is also the issue of where the warhead depot would be.

As with most of the options, Barrow could work but it would be costly and require extensive changes. "The bottom line with all these potential sites is we are talking about huge infrastructure projects like high-speed rail or Heathrow. It's only when the detail is looked at that it becomes clear how complicated it is, and nobody has done the very detailed feasibility [studies] that would be needed," says Chalmers.

4. Ile Longue, Brittany, France
Submarine at Ile Longue Ile Longue base, north-west France

The idea of the UK's nuclear deterrent being based abroad would horrify some in the British military and raise big questions about its independence.

No country has ever kept their deterrent force in its entirety in a foreign country, based on the principle that a country's last resort has to be somewhere where it has total control of it.

However, the UK and France have recently signed up to two new defence agreements.

One of these is for a joint nuclear weapons research establishment - where the two countries will share the hydrodynamic test facilities but keep the data from their experiments separate - at Epure.

And there have been calls for the UK to consider patrols with France, following the collision between Le Triomphant and HMS Vanguard in February 2009.

Trident graphic

It might be possible to expand Anglo-French nuclear cooperation by asking France to host the British nuclear fleet. "I would say that's the best option from economic and ease point of view," says Dr Michael John Williams, a reader in international relations at Royal Holloway, University of London.

Tusa told the Scottish Affairs Committee there was also a precedent for storing warheads abroad.

"We shared American storage facilities for nuclear warheads at Iserlohn for 40 years and no-one seemed to care. There were American, German and British guards. The UK had British bunkers on German soil, but it was a US sovereign base. I did not notice anyone caring one way or the other," he said.

However, Ritchie says a separate nuclear submarine base and nuclear armaments depot would have to be built in France because of commitments to the UK's nuclear safety regulatory authorities and Nato.

That would be a problem at Ile Longue - where France's fleet of nuclear-armed submarines are based - because it doesn't have space, according to John Ainslie, co-ordinator at the Scottish Campaign for Nuclear Disarmament, which wants to get rid of Trident altogether.

It also shouldn't be assumed that the French would be prepared to have a sovereign foreign nuclear weapons base on their territory, says Ron Smith, professor of Applied Economics at Birkbeck College, University of London.

5. King's Bay, Georgia, US
Kings Bay, Georgia

The equally radical idea of re-siting to the US raises similar questions over independence as France.

However, Trident is a joint venture between the UK and the US. Trident II D5 missiles are leased from the US in King's Bay, Georgia.

British submarines return to Georgia for their maintenance on a regular basis and the UK contributes £12m a year to the US as part of the running costs of the base. Non-nuclear warhead components are also made in the US.

Past UK prime ministers have always stressed Trident's independence, saying its firing does not require the permission, the satellites or the codes of the US.

But Ritchie says there has always been a degree of controversy over the "incredibly high level of US support that allows the UK to remain a nuclear weapons base".

Despite the "special relationship" between the US and the UK, as with the France option, there would be massive political obstacles to be overcome.

Essentially it comes back to independence. "Even when countries get on well, they can disagree. For the UK to have its ultimate security guaranteed, it would want to be fully independent," says Williams.

6. It could stay put
David Cameron with Commander John Livesey aboard HMS Vanguard, 2013 David Cameron with Commander John Livesey aboard HMS Vanguard, 2013

The Scottish government says it is committed to removing Trident if it becomes independent and maintains it would not negotiate with the UK in exchange for concessions on other issues such as national debt and currency union (the UK government has ruled out the latter anyway).

But Ron Smith says there would be considerable pressure within an independent Scotland to do a deal and create a type of Sevastopol military enclave as Ukraine did, before Russia took over the Crimea.

The UK would be under pressure to do a deal too because even if it was feasible to replace the Clyde naval bases - "and it's not clear that it is" - it would be incredibly expensive and time consuming, he says.

But Ritchie thinks the scenario is unlikely. "The SNP has staked its political credibility on getting rid of Trident - it's unlikely to concede. The MoD would also find it very uncomfortable to have the UK's nuclear deterrent in another country, even if it was a sovereign UK territory," he says.

Earlier this year, First Minister Alex Salmond, leader of the SNP, ruled out the prospect of a "Cyprus-style" leaseback scheme. Chalmers says this is a distraction. "A sovereign base area would be UK territory, but a foreign base is different. The SNP has already conceded four years of basing to 2020, so there is no point of principle in extending this for some more years," he says.

Another option would be to change the UK's nuclear deterrent to an airborne or land-based system, according to Williams. However, they have been dismissed as too vulnerable and highly problematic the past.

But Chalmers believes it probably would be possible to find an alternative home for Trident - "given time and political will". But it would not be easy, he says.

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Here are a selection of readers' suggestions for other places Trident could go.

They could relocate to Scapa Flow if Orkney (and Shetland) were given the right not to be part of any independent Scotland, should their votes in September be in favour of Union. Still an expensive option.

Steve Cobb, London, UK

Could the Royal Navy move the Vanguard submarines to the North east for example the Jarrow /Hartlepool areas and find a nearby area to store the warheads, we would welcome 8000 jobs with open arms in this area. There are coastal areas that aren't tidal and Hartlepool used to be a Royal Naval dockyard which would hold strategic significance with it being a North Sea coastal area.

Richard Stoker, Bishop Auckland

Weymouth would have been idea place but MPs have screwed up that option. So how about the Falkland Islands.

Roger, Oxon

How about placing the Trident Program on a mid-Atlantic Island such Ascension or some other. After all this was used during the Falklands campaign.

Dermot Mills, Dublin, Ireland

What about Portsmouth?. It is a larger Dockyard than Devonport. The channels leading to it are already being dredged for the new carriers. Portsmouth's other advantage is there are a lot of other naval establishments close by which may help with the missiles. Biggest problem is there are lots of people, they may not want it, but they are trying to keep the dockyard open.

Simon Board, Magor, Wales

This is sailing ship thinking. The days when natural harbours were the only option are long gone, a new facility could easily be constructed close to shore and probably off the North Devon coast where there is deep water relatively close to the shoreline. Alternatively incorporation into a future Severn Barrage might even be an option. The cost of and relocation to a new site would not be as expensive or as difficult as imagined once people star to consider the problem rationally. Existing nuclear facilities like airports are always expensive to extend and develop where as a greenfield project free of the normal operational constraints is cheaper and faster to build and does not have to compromise on safety. A solution just needs joined up thinking. This is not a difficult project to construct and the south west would welcome the jobs and it would not be that far from Devonport, just build new land like everyone else!

Steve T , Bridgwater, Somerset

How about putting the nuclear facility off the Isle of man or even Isles of Scilly somewhere? Going to France or even Wales could be a future problem. If we have a disagreement with France in the future or Wales seeks independence there's another timely and costly move. Another alternative could be Foulness, Isle of Sheppy.

Philip James, Great Dunmow

What about Strangford Lough, in Northern Ireland? It has a fairly narrow entry channel, but once in the lough there would be enough room to have the submarine base and warhead storage on opposite sides.

Sam Fitzgerald, Cambridge, UK

I'll nominate Ramsgate! Since losing all of its cross channel ferry operations there, there is a large docks area doing nothing except for marina operations. I'm sure the local population would appreciate the jobs!

AJ Steele, Esbjerg, Denmark

Put the boats in the Thames. Why should London get all the cultural money, the investment money, etc., and expect the rest of these islands to look after the nasty or dangerous bits?

Alan Atkinson, Kent

They could be based in Bermuda, we are a colony midway between the USA and Europe.

David duMont, Paget, Bermuda

If Scotland 'wins' independence in September, it is likely that Orkney and Shetland will seek greater devolution, if not independence themselves. Orkney (Scapa Flow) might make a suitable base. Milford Haven wouldn't be suitable because of access - and a conflict of interest in terms of safety with the refineries. The arguments already made against Devonport rule this location out.

Michael Leek, Portknockie, Banffshire

Perhaps one wildcard option might be to build a new base on sovereign British territory, but not necessarily within the British Isles. Although the African Nuclear Weapon Free Zone Treaty, to which the United Kingdom is a party, includes a number of Islands in the Atlantic, it does not name the islands which make up the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha as being prohibited from storing or basing Nuclear Weapons. This would obviously be a last-resort option, but it is food for thought nonetheless.

Jonjo Robb, Haworth, United Kingdom

When you consider the D5 range, and potential, if any targets - Russia, China, the Middle East etc, then why not use the large military base we already have far from any population and jointly run with our 'American cousins' - Diego Garcia would seem the ideal location.

Richard Terry, Edinburgh, Scotland

Fishguard in West Wales? There is a separate disused weapons storage facility at what was RNAD Trecwn. My grandfather used to work there in the 1950s.

David Buckley, Glasgow, Scotland

Carrick Roads was the navy's original choice before Faslane years ago. It's deep enough to get in and out under water. Would have been brilliant and still can be. Faslane is horribly vulnerable due to the Rhu narrows.

Roland, Uxbridge Middlesex

I would have thought Diego Garcia would have been ideal - it's British overseas territory anywhere, with almost no population to think about, protected from most tsunami by the undersea geography, and currently rented out the the US Military as a base for B52s and suchlike.

Allan Wallace, Gloucester, England.

How about a Trident base on the west coast of Australia somewhere between Perth and Darwin? I believe there is a new US base in Darwin being set up. Very sparsely populated for safety concerns, away from busy shipping lanes, and with a friendly English speaking population: still with the Queen as head of state. Would give easy access to the Indian Ocean for a Middle East conflict or the Pacific for any Chinese or Korean conflict.

Roger Mantell, Chertsey

What about Lundy in the Bristol Channel? It's far enough away from any towns and cities. The warheads could be stored on one side and the subs on the other and although not a great distance they would be separated by solid granite. The road route from AWE Burghfield and Aldermaston is a simple pootle along the M4 rather than driving the whole length of the UK.

Andy, Reading, UK

Plenty of land to build a new base in Manchester, at the end of the Ship Canal.... 35 miles inland.

Steve Johnson, Manchester, UK

What about Gosport and Portsmouth? Gosport was the home of the submarine fleet for many years' in addition it has an armament depot and the skills to deal with the warheads. Portsmouth has all the necessary skills to transfer to maintaining subs, especially now it has lost the shipbuilding contract. Both towns have a long history of supporting the Navy and a proud attachment to it.

Vivien Tarrant , Andover, Hampshire

Cornwall is best place, they would welcome the investment, jobs, industry. Attracting top qualified people to the area too. Davonport is not suitable, however is best placed. A new base in Cornwall would be capital investment should HS2/3/4 be added to with a line to Cornwall as nuclear material should always be transported by rail. so, win, win, it's Cornwall. From a 52 year old living in Lincolnshire, but hailing from London.

Paul Higbee, Louth, Lincolnshire

What's wrong with Hull or Goole? Goole is one of the deepest ports in Europe and inland. Hull would be a convenient nearby port.

Patrick Naughton, Doncaster

Why not Gibraltar as this has a nuclear license and is still under UK sovereignty. The strategic launching pad this would create and submariners would enjoy tropical sunshine rather than dismal weather in Faslane.

Gerard Murray, Plymouth, Devon

Why not move the facility to Middlesbrough to the closed ship building facility at Port Clarence. The missile facility could be at Hartlepool on the other side of the river. Would massively help an unemployment black-spot.

Graham Naughton, Middlesbrough, Cleveland

If Barrow is dredged properly to allow year round access, then a missile depot could be sited within a reasonable steaming distance north, as it is mostly sparsely populated. They may not like it too near the nuclear site at Seascale (Sellafield) but even slightly further north on the English side of the Solway firth has reasonable water access without major conurbations.

William Walker, Portsmouth, UK

The river Humber would be an ideal choice as it is fast flowing and has one of the deepest ports in Europe, there is an expanse of waste land around the docks including offshore structures that were originally used as Gun emplacements, that could be modified as weapons loading and storage areas, plus there are several RAF bases in close proximity to provide security.

David Clarke, Nottingham, UK

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