"We Must Prevent A Minefield Gap" - Royal Navy Mining Plans for WW3

 

 

Sea mines are one of the most lethal and effective ways of exercising sea control. Used defensively they can control an opponents freedom of movement, preventing easy access to certain areas by hostile forces, or ensuring that particularly sensitive locations are protected. Offensively they can be used to cause disruption to an opponents plans, bottling up high value assets in ports and anchorages until swept and declared clear of mines. In wartime this may disrupt planning, or impose an unacceptably high cost to push through suspected minefields – a classic example of this was the use of Type 21 Frigates in the Falklands War to conduct recce missions of potential landing areas ahead of the invasion to identify if mines had been laid.

The UK has long been a leading player in the field of mine countermeasures, maintaining a large and effective force of ships, and increasingly remote platforms to investigate shipping routes for mines, identify them and eliminate the threat as required. Throughout the Cold War the Royal Navy operated a large force of MCMV’s for both in shore and coastal sweeping, as well as deeper ocean work. The workhorse of the fleet was the TON class, which was the last wooden hulled warship built for the RN, as well as the HAM class inshore vessel. Both were built after the Korean war in large numbers, (115 TON class and 93 HAM class) and used both as regular vessels, and also held in reserve for wartime. Later on the RIVER and HUNT class provided the backbone of the late Cold War fleet (of note is that the HUNT class has now been in RN service for longer than the TON class). Other plans called for the use of trawlers to be taken up from trade and crewed by reservists for deep ocean sweeping operations.

The RN’s role in cold war defensive mine countermeasures is relatively well known and understood, but there is far less awareness of the use of naval mines as a weapon system. The RN held stocks of mines throughout the cold war, only disposing of them in the early 1990s without replacement, but far less attention has been paid on the role played by minelaying in wartime from both an RN and NATO perspective. The purpose of this PSL article is to look at files from the 1970s held by the National Archives in Kew which present a fascinating story about a previously little known part of the Cold War.

UK MOD © Crown copyright 2021

In 1971 the MOD commissioned work to review existing policies and plans for mine warfare by the RN and in turn assess whether air launched minelaying would be credible or viable in wartime. The resulting study can be found online (United Kingdom Minelaying Capability) and is helpful in that it starts by reviewing wider mining plans. The agreed definition of minelaying is:

“Defensive Minelaying is conducted in waters under one’s or allied control…  Offensive minelaying is conducted in waters which are partly, or wholly, under the control of an enemy”

The report was clear that NATO had plans in place for both offensive and defensive minelaying in the event of war, and that the UK planned to make contributions to the defensive plans.

The report noted that mines would be of two major types – mines laid on the sea bed (ground mines) and  buoyant mines that floated or were moored in position. It was noted that “the latter are rarely used and are contrary to the Geneva Convention”). Mines worked by detonating in a variety of ways, usually triggered by pressure, water or acoustic signature, and had a variety of settings that could prevent them detonating on friendly vessels, and were designed for different activations, for example waiting for a certain number of ships to go over them, or prioritising specific ship types. This makes mines a powerful weapon as even if one has gone off, you don’t know where the next one is, or when / if it will detonate. The only way to be certain that you are safe is to clear a route through the minefield, which in turn is slow, and requires slow, vulnerable specialist ships and teams. In wartime this makes minefields a powerful defensive asset as an enemy is unlikely to be able do this in your waters without being detected and attacked.

The 1971 paper also noted advances in mine technology since WW2 including the emergence of “torpedo mines which are released by influence and hunt their targets, thus having a wider effective radius), deep laid mines which rise or propel themselves up to explode at target depth) and buried mines (which are difficult to detect by minehunting, sonar or divers)… However the UK does not possess these weapons and little UK research or development has been carried out on maritime minelaying in recent years”.

The paper went on to discuss how minelaying had been used historically during operations, noting that it was effective at blockading ports or forcing the enemy to focus resources on one area. Of particular note it identified that: “during the Second World War aircraft were by far the most prolific and generally the most successful mine laying agents, and achieved these results at relatively low cost”.

In the context of 1970s planning, NATO intended to carry out both offensive and defensive minelaying operations. The latter was by far the more straightforward, as it could occur during the anticipated ‘transition to war’ period and would see a variety of minefields laid around NATO waters to improve security and make life harder for Soviet forces. SACLANT (Supreme Allied Commander Atlantic, who would fight the maritime battle and was designated as the NATO mining coordinator) anticipated that defensive minelaying would: “contribute to the ASW defence of shipping in the approaches to Europe and to provide ASW protection in the anchorages”.

In other words the role of mines would be to ensure that Soviet submarines would be restricted in their ability to target shipping in vulnerable chokepoints, while ships forming up to unload cargo and personnel in major port areas would be protected – reducing the chances of another ‘ROYAL OAK’ incident as occurred in Scapa Flow. While not foolproof, it would make it harder for the Soviets submarine force to target merchant shipping except on the high seas.

The offensive mining plans called for NATO to lay minefields to cause disruption in the following areas:

“North Africa and Levantine Ports: To restrict the use of these ports and bases  by enemy forces.

North Russia: To disrupt enemy naval, and particularly submarine, movements to and from enemy ports”.

This 1970s perspective highlights the two very different maritime battles that NATO expected to fight. The challenge politically was that laying minefields ahead of war breaking out for offensive purposes was politically impossible – as the paper went on to note: “Although SACLANTS views have not been finalised, the draft mining directive states that political considerations mitigate against offensive minefields being laid prior to the outbreak of major aggression except as a calculated act deliberate escalation. However once major aggression has broken out, offensive mine warfare can be used without political restriction in order to contain and reduce enemy combatant and merchant shipping. Although SACLANT therefore regards the mine as a relatively inflexible weapon, the Navy Department considers that it could have a very important role to play in a period of tension as a means of temporarily neutralising  an area where confrontation is imminent. However such a role would call for a speed of response which, at the longer ranges, could only be provided by aerial minelaying”.

For the Royal Navy then the challenge was how to support these two principles, of delivering both offensive and defensive mining. To engage offensively would be a challenge as it would require sending either vulnerable surface ships, or submarines to northern Russia to be ready to lay minefields, but doing so at the cost of not being on their intended war stations, and lacking suitable offensive weaponry to carry out their war mission, once hostilities began. This was a high risk gamble for a fairly low gain operation. The RN view was simple about the prospects of offensive minelaying

“We do not envisage the use of minelayers in the offensive role as their vulnerability is such that they are unlikely to be successful in waters which are partly, or wholly, under the control of an enemy…”

The decision was taken then in 1971 that the offensive mining plans of SACLANT were, at that time not deliverable except by submarine, and then at the cost of taking vessels off their war role. The only two other options were air delivery, or relying on technological advances to allow remote mine control. It was suggested though that from an aerial perspective, this was a highly risky option:

“The UK has no aircraft cleared for minelaying. Buccaneer, Vulcan and Nimrod aircraft could meet the requirement… a Vulcan could, for example, carry up to 25 mines and a Buccaneer 9… However the acceptance of an aerial minelaying role could only be at the expense of other roles.  As a guide, between 60-70 generation mines (or alternatively only one of the homing mines being developed in the USA) would need to be laid per mile of width to provide a 70% threat to all classes of ship”

In other words, to use aerial minelaying would impact on the UK’s ability to carry out long range maritime patrol, conventional strike or tactical nuclear missions and would require a lot of aircraft that were easily detectable to lay these mines. The risk would be high that pre-war it would be seen as an escalation, while during the war, the use of nuclear bombers like Vulcan on missions to approach the northern Soviet coastline could of itself rapidly escalate matters from the conventional stage if the aircrafts mission wasn’t understood. As such the view was taken by SACLANT that “Aircraft which could deliver aerial mines have tasks of higher priority in current plans and thus were not available for offensive minelaying” .

The end view on offensive minelaying was that the only point where it would be valuable would be if technology enabled the development of remotely armed mines that could be activated when required – rather than being laid as an overt act of war, these could be put down covertly ahead of conflict, left in position and then armed as and when required or as the paper put it:

“we understand that the USN is investigating the manufacture of a controllable mine, the ultimate aim being for control to be exercised by patrolling warship, submarine or overflying aircraft. This might help change the balance of advantage in favour of offensive minelaying as a controllable mine could be used within a strategy of graduated response. It remains to be seen whether this would offer a cost-effective way of countering the Soviet naval threat”.  

With offensive mining seen as politically challenging and hard to deliver, the RN focus was on the use of defensive minelaying, which was far easier to manage. Plans during the later Cold War focused on the UK using defensive minefields in two specific locations, that would be used to pose a threat to Soviet submarines threatening shipping and NATO naval forces. The intent for these minefields was that:

“the UK plans to requisition two civilian ferries, provide nucleus crews and equip the ships to lay “deep trap” minefields in the North-West and South-West approaches to the British Isles. Surface ships would be able to pass over these fields, but any submarines passing through them would be at risk. Special equipment for these ferries has been manufactured, and a stock of mines is held for this requirement”.

HMS ABIDIEL - copyright unknown

The UK detailed plans for this role were not covered in the 1971 paper, but a separate paper, also to be found in the National Archives written in the late 1970s provides significantly more detail on the RN’s mining plans, which were far more advanced (and risky) than is perhaps realised. Indeed by 1979 it appears that plans had changed considerably and that offensive mining was both ‘back on the table’ and central to many NATO plans. A study was done in the late 1970s on the RN mining capability and what would need to be done to make it relevant for the 1980s. According to this paper, in addition to the “deep trap” minefields, further plans existed for the laying of surface minefields off major UK ports and anchorages to help protect them from harm.  

The UK stock of mines held during the late Cold War was not exactly modern, in fact it was highly dated and of limited operational value. By 1979 the RN assessment of British mining capability was that it consisted of mines, all of which dated back to WW2, and which could in extremis create a total of 1,170 ground mines and 4,380 buoyant mines to be laid in minefields around UK waters. This initially sounds quite impressive until you read the very heavy caveats that the RN placed on this figure.

“The dated technology of these mines requires them to be laid in dense fields in order to achieve an adequate threat to enemy forces: the stock is too small for this to be done on the scale envisaged for a realistic contribution to either ASW defence in UK shallow waters or to satisfy NATO requirements. Furthermore due to an inadequate minelaying capability, the time required to lay the fields is considerable. The planning for protective fields currently in progress is highlighting the ineffectiveness of current UK mines and the paucity of minelaying effort.”

In practical terms what the planners were highlighting was that were a decision taken to go to war, then there would be real difficulties in both getting the minelayers ready and in getting a decision to lay the minefields. From the former perspective, the MOD plans relied entirely on two civilian roro ferries that were to be taken up from trade – these ships were the ferries ULSTER QUEEN and ULSTER PRINCE, both of which were used as car ferries between Belfast and Liverpool from the late 1960s. It was not widely known that the Royal Navy had manufactured the specific equipment needed to convert them to minelayers as part of the War Book ‘transition to war’ measures and that plans, on paper at least, were well advanced to do this. The problem though was these ships were not ideal for the task. Although minelaying kits existed, it was estimated that conversion for both ships would take at least 5 days to carry out as they were fitted with the rails, and their crews arrived. Also, as the RN wryly noted:

“Although it has been assessed that approximately 5 days will be required for conversion and for the fitting of minelaying equipment, this has never been proved, nor have the ships ever carried out any form of minelaying trial. These ships are due for replacement by larger new build ships in 1982, for which plans are in hand to allow for conversion to minelayers”

Intriguingly it is hard to work out if the replacements ever actually entered service – wider research shows that in 1981, P&O Ferries, who operated the Liverpool-Belfast line closed the route due to its significant losses incurred. To date the author has not been able to identify the replacement vessels, or if they were completed or not.

The next difficulty the minelaying plans would have encountered is that of time. The assumption was that transition to war would potentially occur within 7 days, although perhaps longer. During this pre-war phase the Cabinet would have had to approve the taking up of ships from trade, the call up of reserves and then the conversion itself. It is doubtful that much time would have existed to get the ships to a point where they were usable, let alone able to lay mines before war broke out.

The crews for these ships would have comprised a mine warfare team of 4 officers, 14 senior ratings and 78 junior ratings, all of whom would have had to be trained at HMS VERNON in Portsmouth before going to join the ferries in Liverpool (or another location).

Even had the conversion occurred, they would have had to have sailed to RNAD Milford Haven, which along with RNAD Trecwn, housed the UK mine stocks. This was recognised as a serious challenge as although the facilities were safe, they would have required a 48hr round trip to lay each minefield in the Northwest and Southwest approaches. The reality is likely to have been that during the chaotic transition to war period, the minefields would probably not have been laid by the time war broke out.

Given these limitations, by 1979 it was recognised that UK mining capability was wholly inadequate, and significant efforts were being made to try, on paper at least, to modernise it and align it with wider NATO plans. This seems to have coincided with a shift in NATO thinking towards using offensive minelaying as a capability again, brought about by the improved technology that had been developed, permitting more control over mines and when they would be activated. To that end detailed work was undertaken to look at how the Royal Navy could work with the US Navy to provide both offensive and defensive mining capability into the 1980s that would support wider NATO goals.

The 1979 RN paper identified that there was against NATO planned targets, there was a shortfall of at least 1700 mines in the UK arsenal (roughly 30%) to meet existing NATO requirements as well as emerging ones for minefields in both the Channel and North Sea. These plans called for the UK to lay 650 buoyant mines, 24 ground mines and deploy by Submarine no less than 400 buoyant mines and 400 ground mines while providing a further 500 air laid mines (although there was no specific air frame available to do this). The scale of this ask was considerable when it was noted that the average SSK could only carry 20 mines, and an SSN 30-  to lay 800 mines would require 40 OBERON class missions to deliver, at a time when the RN only had 13 O boats in commission… It was also noted that as offensive mining seemed a credible plan again, the RN may find itself tasked to use its SSN force to carry out offensive mining against Soviet coastline targets as part of wartime operations – a big ask for a scarce submarine force.

Separately for purely national mining needs, there was work in place for the development of a new UK/US Joint Mining Concept, set up in 1978 to focus planning on how to take forward mining operations. The role of this group was to ensure coordination on developing mining plans, development of future capabilities and focus on the challenges of using mines as a credible weapon in wartime. It is clear that the RN and USN were far more integrated than perhaps realised in this space.  

One part of this plan would see the use of new minefields in the Southwest approaches, based on ground influence mines to target submarines and requiring around 3000 mines to replace older stock. There was an ongoing debate about the effectiveness of such a plan – the RN identified that laying an ‘inner barrier’ “from Ireland to Ushant” would be laborious and also given that Soviet SSKs were unlikely to try to penetrate such a space, potentially time consuming and a waste of resources and even if they were in the area, were likely to be easily detectable.

Additional work had been done to develop improved concepts for purely national defence plans for mining involving the defence of the Clyde approaches, which were home to the RN and USN SSBN forces at Faslane and Holy Loch respectively, and which in wartime would be surging submarines out to ensure the survival of the strategic nuclear deterrent. Plans were put in place to improve the quality of the bottom laid minefield, working in conjunction with a new fixed array in the Clyde area to help detect incoming which would need about 1500 mines laid to deter against SSK’s and potentially up to 3000 mines to deter SSN’s given their stronger hulls being more resistant to shock.

This is a fascinating snippet into the planning that went in for the survival of the SSBN forces, showcasing how the UK and US saw defensive mining as being utterly vital to deterring Soviet opportunistic attacks, but also the importance of timing to getting these fields laid ahead of conflict beginning.  

Ulster Prince in dock - copyright unknown

One note of particular interest from the 1979 plan is the comment about minefield planning and how difficult it was to lay mines, due to the challenges of environmental conditions and bottom topography as well as the threat and vessels used to lay the minefield.  Unlike in WW2 which called for dense mines, the battles of the 1980s would require:

“In order to provide flexibility, it is necessary therefore to have either innumerable plans readily developed or the capability to develop new plans quickly in the face of altering circumstances. This calls for a computer… In the past because of their limited effectiveness mines were laid in dense numbers in order to achieve a credible threat. Nowadays with the application of modern mine technology… the laying of the fields requires careful and detailed planning and a need is therefore identified for the UK to possess a computerised minefield planning facility. Meanwhile there is available to the UK a computer programmed for minefield planning at the HQ of the Commander Mine Warfare Command at Charleston USA… future UK minefield planning can be progressed employing these facilities until the UK obtains the proposed Computer Facility for Mine warfare (COFAM) in 1983.”

In an age when Defence uses computers constantly, it is mildly amusing to see references to the use of a primitive computer in the singular, although cynics may argue that COFAM is probably still more fit for purposes than the average MODNET laptop…

Separate to this planning work, significant attention was paid to the potential to update the stockpiles that dated back to WW2. In 1979 the UK mine arsenal was still built around legacy mines and practically no work had been done on developing this since 1945. It was proposed to instead carry out an update of the 1170 ground mines held in store, that would provide an updated electronics package and help keep them relevant into the mid-1980s under a new Naval Staff Requirement.

It was at this point that the RN envisaged using modern technology to ensure that the minefields were fit for purpose, for example adopting ‘microprocessor technology’ to help provide programming for firing rules to prevent a mine detonating under the wrong vessel, or ensuring that it could only fire if it detected the parameters of (for example) a Soviet submarine.

The paper called for further investment in new mines, both updating the legacy ground mines with new IT to provide a stockpile of around 1170 devices, while also investing in the development of a Continental Shelf Mine (CSM) that would be a tethered mine usable at depths of 50 to 250m to target submarines, and potentially surface ships. The idea was that this mine would replace the older buoyant mines that dated to WW2. Finally it briefly considered acquiring the US based ‘CAPTOR ‘ mine (an encapsulated Mk46torpedo), but it was agreed that the USN would lead on deep water mining tasks in wartime.

A key challenge for the 1980s was delivery of the mine capability, with the sole exercise minelayer owned by the RN (HMS ABIDIEL) deemed unsuitable for use in wartime as a minelayer due to her significant constraints as a platform. It was planned that instead she was likely to be used as an MCM support platform for the MCMV forces (a role that she had regularly carried out during her life). Similarly the ULSTER class RORO ferries were due to leave service in the early 1980s, with hopes that they would be replaced, although there were concerns about the minelaying equipment that they would be operating and whether it was fit for purpose (described as a ‘somewhat archaic minelaying system’).

To overcome these challenges, the RN proposed several solutions. The first was to make use of the new ferries ostensibly being built to replace the ULSTER class, while the “future OPV” design was also seen as being valuable for minelaying. This design later became the CASTLE class, two of the most valuable OPVs used by the RN in the 1980s and which remain in service to this day. Both hulls were equipped with a theoretical ability to lay mines, although its unclear if this was ever tested in practise. Another suggestion was the use of hovercraft for minelaying, although again this was never actually carried out.

COUNTY CLASS - Copyright unknown

The most practical suggestion seems to have been the proposed conversion of COUNTY class DDG’s into minelayers. This was actually a good idea as due to the design of the ship, the seaslug missiles used were assembled along a large central corridor, before emerging onto the missile launcher. This would have made conversion into a minelayer significantly easier, and provided the RN with a pair of converted DDG’s with a much higher level of survivability than other surface platforms, and the speed to get to the intended minefield locations far more quickly than converted roro ferries.

In addition to the surface vessels, the paper was clear that submarines would be playing a key role in minelaying for both SSN and SSK’s, although a specific challenge with loading them was the lack of suitable berths near RNAD Milford Haven. Infrastructure was a challenge, given that this location was unable to berth larger vessels like DLGs or SSN’s, which would have meant a not insignificant upgrade to make it feasible for use by submarines, at a likely significant cost.

The final consideration was over using aircraft for delivering mines, something which as noted had previously been dismissed in 1971. By 1979 there was a move in favour of looking again at this concept, driven by:

“USN studies (that) have emphasised the importance of using aircraft to reduce the overall time required to lay minefields… VCAS (Vice Chief of the Air Staff) has proposed, and VCNS (Vice Chief Naval Staff) has agreed that a study be carried out into the RAF reacquiring an aerial minelaying capability in the context of RN mining plans. Initial investigations, including the visit of an RAF team to the US have confirmed that several types of RAF aircraft could be configured for minelaying at a relatively low cost. Finally a study has been carried out into the capability of airships in maritime roles, including minelaying”

It is notable that as late as 1979 there was significant senior RAF and RN support for the use of aircraft in this role, potentially including the Tornado and the C130 Hercules. The report went onto highlight that in addition to these platforms:

“The Sea Harriers conventional bombing capability would enable it to lay mines… however the small number embarked and the CVS’s limited bomb storage areas may reduce the attractiveness of the tactical mining role. The possibility of employing suitable UK civil air cargo aircraft in the defensive minelaying role should also be considered…”

The final piece of the puzzle was the challenge of infrastructure. As noted RNAD Milford Haven wasn’t deemed suitable for the loading of mines onto SSN’s or larger vessels. It was also clear that a significant amount of funding would be needed to sustain these sites to keep older mine types working, while also requiring a lot of investment to make them future proof for the more modern proposed systems that the RN wanted to acquire. Geography also did not help, given that Milford Haven, located in South Wales, was a significant steam from the NW Approaches, which in wartime could be of concern. Instead it was proposed to store mines in the Clyde area for both offensive and defensive mining purposes, mirroring the US Navy which at this time kept a stock of submarine launched sea mines in Glen Douglas, and air launched mines at RAF Machrihanish.  

HUNT Class

Brought  together these ideas represented a significant investment of time, money and infrastructure to provide a credible capability in wartime. What is less clear is how much of this actually came to be though. The archives are full of files of studies into subjects that never materialised, and its probably safe to assume that despite the strong advice to proceed, funding for much of the mine improvement work was cut in the 1981 Defence Review.  Certainly RNAD Milford Haven closed in the late 1980s (the precise date is unclear), presumably as the need for defensive mining passed. RNAD Trecwn too closed in 1992, with the site being sold off in 1998. Today there is no physical depot infrastructure left for sea mines in the UK.

The paper summary though makes grim reading, having assessed the requirement and capabilities on hand, it assessed that:

“current surface minelaying assets are inadequate and of slow reaction and are barely capable of handling the small national defensive minelaying requirement… The time required to lay the planned protective and defensive minefields and the limited effectiveness of our mine stocks call into question the UK’s credibility to satisfy the NATO policy requirements”.

Sadly it appears that this work fell victim to defence cuts and nothing more was done to progress it. Its perhaps understandable – the cost of converting a DLG into a training ship and minelayer was estimated in 1979 prices as around £80m (some £385m today) making it an easy cut to make. Similarly no progress seems to have been made on the RORO ferries, and no modern mines were developed. Its not clear when the RN withdrew its stockpiles of mines – given their age, they would probably have been an easy target in the 1990s Defence Review as an obsolete technology no longer required now that the Soviet Union had gone. Its also telling that HMS ABIDIEL was paid off without replacement in 1987, while the various RMAS vessels that could lay exercise mines have also long gone. The proposed conversion of a COUNTY class never happened, while it seems unlikely that any new mines were ever purchased by the RN in any meaningful numbers. What seems most likely is that the stockpiles existed into the 1990s without major update and were then quietly disposed of. In a similar vein, the kit for minelaying RORO ferries was almost certainly lost many decades ago. While there may be a small number of practise mines out there for training, it is clear that the RN lost its ability to lay minefields many decades ago, and shows no sign, or interest, in recovering this capability.

There are lessons aplenty though for the modern Royal Navy here. Firstly the importance of maintaining a list of ships to take up from trade when needed. The 1970s was a period when the MOD continued to have strong interests in the UK shipbuilding industry, and many different ships had subtle modifications made for possible STUFT roles – for example the Atlantic Conveyor and her sisters were built and intended for conversion into the Arapho role. Reportedly the BP tanker fleet was also intended to be rapidly converted into emergency tankers for RASing at sea. Today none of these capabilities exist, and its clear that the MOD has long lost interest in supporting domestic shipbuilding in this way. This shows that in a crisis, the platforms to be chartered may well not be British in origin.

The ongoing importance of the Clyde to UK defence means that there is an interest in protecting it. But this in turn is far harder to do without minefields and a seriously depleted Fleet Air Arm ASW force. In turn though the likely threat is far smaller too – there are far fewer Russian SSK’s and SSN’s available for sea, and in wartime they’d be hard pushed to pose a threat to all the locations that NATO wants to protect – and the likely indicators and warning of the Northern Fleet putting to sea and its war stations en masse is likely to be quickly detected. Is there then a need for minefields in the modern operating environment?

RNAD Milford Haven today

The RN thinks that the mine is still a threat, but its focus has been on taking the minehunter out of the minefield, spending a significant amount of time and resource on the next generation of remote platforms to go into the likely mine locations and conduct surveys of the ocean floor, and be ready to respond to a threat. The RN has intentionally chosen to rapidly draw down its once substantial MCMV force and instead make this a predominantly shorebased capability, although the RFA STIRLING CASTLE was intended to try and provide a mothership function to the new vessels. Sadly, the complete collapse of the RFA to the point that it can no longer provide a credible support capability to the RN must call this long term capability into question. What this highlights though is that urgent action is needed to identify how the RN would tackle mines in a future high intensity operation, given it lacks the ships, the support ships and the people to address this at present. It is profoundly depressing how easily a capability and credibility hard won over literally decades of operations appears to have been thrown away at the altar of progress without any sense of contingency planning for what to do if things don’t go as planned.

Another relevant lesson is resource based. There are never enough platforms to do the job you want them to do and they will be in high demand. The future RN is likely to have no more than 3-4 SSN’s available in wartime, meaning that if you want to do offensive mining of Russian ports, this will tie up the majority of the force. In the Cold War to carry out NATO plans as intended would have meant the entire RN submarine force doing that over other tasks – was this credible, or was this an example of providing theoretical solutions to problems that wouldn’t actually happen, and cause problems in wartime? Similarly, there seems to have been a disconnect between the use of aircraft types and their role – the idea of using nuclear capable bombers in a mining role may have been technically feasible, but also a huge escalatory risk if misunderstood.

Another key lesson is the problem of having a capability that requires political decisions to deploy. Mines presented a very real and capable offensive option for NATO, but the challenges of being a defensive alliance, and the issues of trying to get approval to lay a minefield in peacetime to prevent a Northern Fleet breakout (without even considering the issue of what this would mean for SSN’s getting to war stations) must call into question why you would have a policy like this in the first place. The reality is that offensive mining was great on paper and fell apart the moment it hit the NATO policy space.

The last big lesson is that preparing for war is about assuming that you have time to make your plans happen. The RN mining plans called for activities that would occur on a very tightly scripted timeline, often at odds with the wider war book measures. We cannot assume that a future conflict would work to our timelines, or that finely made plans will survive first contact with the chaos likely to ensue during transition to war. We should expect to fight with what we have, not with what we expect to have if everything aligns perfectly.

Overall these files are a fascinating insight into a now almost forgotten world of minelaying and operational planning that reflects the traditional role of the RN as the defender of the UK. The use of defensive minefields, the protection of ports and anchorages and the ability to have a capability to take the fight to the enemy is very much a classic role of the Royal Navy. Whether there is a future for mining in a world where Russia is the resurgent threat remains to be seen, but it is clear that had the Cold War gone hot, then mining would have played a vital part in the early stages of the third battle of the Atlantic, potentially saving the RN SSBN force from destruction, and ensuring that, if required, a nuclear strike could have been launched. A grim but necessary task.