Why relocating Trident away from Scotland is virtually impossible

On 18th July the House of Commons voted to construct new Successor submarines to replace the current Vanguard boats that carry the UK nuclear deterrent. The arguments in favour of the deterrent are compelling, delivering cross-party support and carrying the vote overwhelmingly. Unsurprisingly the 58 of 59 Scottish MPs voted against and their defeat will be another ‘grievance’ used by nationalists to push for another referendum on independence. Many in Britain seem to think we could simply move the deterrent from its base in Scotland to England. Here we will look at the extensive Scottish infrastructure that supports Trident and the very limited options for moving it south.

Although around half of Scots are in favour of keeping Trident the issue is used obsessively as a political weapon by the nationalists. The SNP want to axe Trident but be part of NATO, an alliance that includes nuclear capability as an important element of its strength. They give the impression that axing Trident would end poverty in Scotland, yet Trident is just 6% of defence spending and less than 0.2% of total UK government outgoings. Despite their poor record in running the largely devolved Scottish government, they have significant popular support and independence is not unthinkable.

Many people commenting on defence matters under-estimate or overlook logistics and infrastructure, this is particularly true in the case of Trident. When the UK signed the agreement to obtain the Polaris nuclear missile from the United States in 1962 the MoD had to begin an immense project to create the submarine-based deterrent. Amazingly this was delivered within the very tight timescale and the first deterrent patrol was made on schedule by the Royal Navy in 1968. Although the public and media attention was focussed on building the 4 submarines and developments at Faslane, another critical element was the construction of the armaments depot at nearby Coulport.

RNAD Coulport – the crux of the issue

The facility at Coulport is used to store the missiles and nuclear warheads before loading them aboard the submarines. (To save costs, the Trident missiles are actually serviced in joint facility in the United States). Built on the shores of Loch Long, this site is close enough to Faslane to allow the submarines to make a short passage to load or unload missiles. A complex network of underground bunkers, roads, support buildings and jettys was constructed between 1963-68. Replacing the obsolete Polaris missile with the Trident D5 in the 1990s required major new construction at the site because the Trident missile is considerably larger than its predecessor. As an indication of the scale of the facilities, the Trident Works Programme at Faslane and Coulport took 13 years and cost around £1.9 billion (at 1994 prices), the second most expensive works project in the UK after the Channel Tunnel.

The heart of the Coulport site is the Trident Storage Area which includes 16 large underground bunkers with air-locked doors each able to store a single Trident missile. The rocket fuel in each missile has the explosive power equivalent to 70 tonnes of TNT so the bunkers have to be well separated and able to withstand explosions or the very remote possibility of an earthquake. There are also stores for the British-made nuclear warheads which are manufactured and serviced at the Atomic Weapons Establishment (AWE) in Berkshire and are transported to Scotland in regular road convoys. The warheads are joined with the missiles in the Nuclear Process Building and then taken by lorry to the Explosives Handling Jetty (EHJ). One of the world’s largest floating concrete structures, the EHJ is a specially constructed covered floating dock. The submarine enters and the missiles are loaded vertically into the tubes by overhead crane. There is also a separate jetty for loading torpedoes which are stored on the site.

Remote from public gaze, Coulport is one of the most sensitive and well guarded defence facilities in the UK. It is has an area of around 2 sq miles, more than twice the size of Faslane naval base. It has about 20 miles of internal roads and 18 miles of alarmed razor wire fence.

The main features of the extensive Scottish facilities required to support the Royal Navy’s nuclear deterrent submarines.


The base at Faslane has been developed from the 1950s and news facilities have been added continuously until the present day. The large shiplift building can raise a fully armed Trident submarine out of the water for maintenance in a covered hall. There is the dedicated finger jetty for the Trident submarines and the newer 44,000 tonne floating Valiant jetty for use by attack submarines (which cost around £150M). The berths are equipped with backed-up power supplies to maintain and monitor nuclear submarine systems and much of the site is expensively hardened to withstand earthquake, fire, explosion or tidal surges. There are also berths used by visiting warships and the Sandown class minehunters based in Faslane. Ashore there are large engineering workshops and storage areas. In the last decade considerable effort has gone into upgrading accommodation, including construction of the new ‘supermess’, shopping centre and sports facilities. There also a large number of married quarters for service families located close to the base.

Other Scottish facilites

Besides Faslane and Coulport there are other important defence sites in Scotland that either directly support the deterrent or are critical to the RN operations. Three underwater ranges around Western Scotland are used to measure acoustic signature of ships, submarines, torpedoes and underwater vehicles. Located at Loch Fyne, Loch Goil and the Isle of Rona these facilities are critical to ensuring submarines retain their stealth and assist in the development of underwater weapons and countermeasures. It is also likely there are other classified installations around the Clyde area that support the deterrent and listen for foreign submarine intruders.

Besides Coulport there are three other important defence munitions sites in Scotland that support the RN. DM Glen Douglas covers almost 650 acres and has 56 underground magazines. It provides ammunition to RN vessels berthed at Glen Mallen jetty on Loch Long where there is also a naval oil depot. DM Crombie on the River Forth is one of the few depots in Britain with deep water and a jetty that allows the largest warships to load or unload munitions. DM Beith south-west of Glasgow produces, tests and stores missiles and torpedoes. Able to store 18,000 cubic metres of explosives, Beith also assembles Spearfish torpedoes and is involved in handling much of the UK forces’ precision-guided weaponry including Tomahawk land attack missiles (TLAM).

  • RNAD Coulport

    A small section of the secretive RNAD Coulport surrounded by 18 miles of fence. Photo: Wikipedia

  • HMS Dauntless passes the Explosives Handling Jetty on Loch Long where Trident missiles are loaded into submarines

    HMS Dauntless passes the Explosives Handling Jetty on Loch Long where Trident missiles are loaded into submarines

  • Shiplift building and finger jetty at Faslane

    From left to right: Valiant Jetty, Finger Jetty and Shiplift building at northern end of Faslane naval base

  • Minehunter berths and workshops. The accommodation blocks are at the southern end of the naval base

  • Valiant Jetty Faslane. SSNs HMS Ambush and Triumph alongside

    Valiant Jetty, Faslane. Attack submarines HMS Ambush and Triumph can be seen alongside

  • RFA Fort Austin loads ammunition at Glen Mallen Jetty. Photo: Colin Smith / Geograph

    RFA Fort Austin loads ammunition at Glen Mallen Jetty. Photo: Colin Smith / Geograph

Even from this cursory examination of Scottish facilities, it is obvious that replicating them in England would be exceptionally expensive. Although some equipment could be removed for transporting it is clear that huge investment has literally gone into the ground, tunnels, roads, jettys and buildings that can’t be moved. There has been phased construction and development going back more than 50 years at these sites and the armament depot would have to be built from scratch, even if suitable new sites could be found. A very optimistic estimate made by RUSI in 2014 that extrapolated historical costs put the relocation figure (using Devonport) around £4Bn. In the much more regulated environment of the 2020s, such a project would surely run into the £10s of billions. Against this it should be remembered that to decommission the entire nuclear weapons infrastructure in Britain the estimated cost would be around £10Bn.

Alternative sites in the South?

Let us suppose that against the backdrop of reduced tax receipts after Scottish independence, the additional money required to relocate Trident could be found. The MoD has already examined alternative sites and concluded that they all have very serious drawbacks. Not only would the expense of transfer stretch the fragile defence budget to breaking point, and involve additional risks, it would require enormous political will to overcome inevitable strong local opposition.

Faslane and Coulport are about 30 miles from the nearest large population centre of Glasgow, benefit from deep water access and lots of cloud cover that helps obscure them from satellites. With the exception of Milford Haven, alternative locations are all adjacent to large populations. The accidental detonation of nuclear warheads is virtually impossible and the tiny risks are more to do with the explosion of the solid fuel propellant in the missiles. Incidentally, Aldermaston (where warheads are manufactured) is as closer to London than Faslane is to Glasgow. It is a myth that the Scots take all the risks associated with the British nuclear deterrent and Glasgow, the largest city in Scotland, would be a target for our adversaries, whether we had nuclear weapons or not.

Devonport is the leading contender to accept the Trident submarines as it would not require starting from scratch. It can still refit two nuclear submarines concurrently and has nuclear-certified berths. However it being run-down as an operating base for submarines and is nothing like was during its 1980s heyday. Devonport has the space but would still require major development match the facilities of Faslane. Studies have concluded that it would just be physically possible to build an armaments depot just across the Tamar by taking over the Anthony House Estate (owned by the National Trust). Unfortunately it would be very close to the 250,000 inhabitants of Plymouth exposed to the (small) risks of missile explosion and possible plutonium release. Although Plymouth is used to having nuclear vessels on its doorstep, local protest against such a plan involving increased risks and the destruction of a National Trust site would be understandable.

Falmouth is another contender, at least for the armaments depot and EHJ, assuming the submarines were based in Devonport. The plan would involve taking over the whole Penarrow peninsular and demolishing the villages of Flushing and Mylor. The depot would not create many long-term jobs and would impact badly on area heavily reliant on tourism and water sports as well as being too close to the 26,000 people living in Falmouth.

Portland The former naval base and air station close to Weymouth have been considered as a possible alternative to Faslane. Since the base closed in the 1990s the site has been redeveloped as the Olympic sailing centre and Osprey Quay leisure centre which would have to be demolished. The only possibility for an armaments depot in the region would be in an area of considerable natural beauty, taking over the Army’s Lulworth tank training ranges with the EHJ located close to the renowned Lulworth Cove beach.

Milford Haven, Wales has a deepwater port with space for both submarine base and armaments depot. However, the port is now an important energy importing and storage site. Daily arrivals of large tankers and stores of oil and LNG make it incompatible with submarine movements, explosives and nuclear materials.

Barrow in Furness. Home to all British submarine construction, the Walney channel that submarines would have to navigate is extremely shallow and only usable by an SSBN a few times in the monthly tidal cycle – an unacceptable tactical limitation. The potential sites for a submarine base or armaments depot are extremely exposed. Although the site is quite remote from other main population centres, it would be too close to the 70,000 inhabitants of the town.

Foreign basing. It has been suggested that the submarines could operate from Kings Bay, Georgia in the United States. Although many of the US Trident facilities are compatible with the UK deterrent, there would be considerable political complications. Even if US Congress approved the idea, sending British nuclear warheads to the United States would be in breach of the Non-Proliferation treaty (NPT). The deterrent would also become considerably less independent of the US than under the current arrangement. An even more unworkable proposal would be to share the French SSBN base at Ile Longue in Brittany. The site is already very compact with little room for expansion. The RN boats and Trident missiles are considerably larger than the French boats and their M51 missiles and incompatible with virtually all the French facilities. Despite growing defence cooperation efforts, the political implications of basing UK nuclear weapons on French soil would probably be even more convoluted than for the US.

It is hard not to conclude that if an independent Scotland will not allow nuclear weapons to remain on its soil this would probably signal the end of the British nuclear deterrent.

It is clear an independent Scotland would be a disaster for UK defence and the Royal Navy in particular. As Britain moves towards a future outside the EU, it is critical that a strong Union is maintained which would benefit us all. The UK Trident system is critical to the defence of Europe, the UK and Scotland. Those in Westminster must persist in making this case to the people of Scotland while ensuring they serve their interests with equal vigour to those in England.


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