Britain's third £1 billion Astute Class nuclear submarine, HMS Artful. Crown copyright.

Can the United Kingdom sustain its Continuous At-Sea Deterrence? After 50 years of unbroken CASD, reports of technical problems with the Royal Navy’s fleet of nuclear-powered ballistic-missile submarines, as well as COVID-19-related challenges, have added to concern that this continuous at-sea presence is at risk.
The United Kingdom marked 50 years of unbroken Continuous At-Sea Deterrence (CASD) with the Royal Navy’s nuclear-powered ballistic-missile submarines (SSBNs) in 2019, but reports that half its fleet was laid up for over a year recently with technical problems have added to concern that this continuity is at risk. The Vanguard-class SSBNs will now have to operate into the 2030s, well beyond their original planned lifespans, even if the successor Dreadnought class is delivered on time. In addition, the COVID-19 pandemic is causing further complications.

The chair of the House of Commons Defence Select Committee, Tobias Ellwood, drew attention to the potential strains on the CASD mission at a committee hearing on 17 March, when he suggested that two of the four Vanguard class had been ‘out of the water for more than a year’. CASD requires at least one boat always to be on patrol (usually for up to three months at a time). Typically, a second and third boat are either training to take over the next patrol or have just returned and are in maintenance at the boats’ home base at Faslane in Scotland. The fourth, meanwhile, would likely be undergoing a more extended Long Overhaul Period (LOP) at Devonport naval base. Problems arise if there are significant delays in the maintenance and LOP work. That, it seems, has been the recent situation, with CASD relying on just two boats to conduct overlapping rotational patrols.

One of the submarines concerned is HMS Vanguard, in a scheduled LOP since December 2015. Originally planned to last three and a half years, the extensive refit has overrun by about a year so far and Vanguard is unlikely to rejoin the fleet this year as previously intended. The identity of the second vessel, which apparently required extended maintenance at Faslane, is unconfirmed.

There may be particular issues with the boats concerned. But, with the Dreadnought class now not expected to enter service until the early 2030s, the Vanguard class will likely have to serve for 37 to 38 years, well beyond their original design life of 25 years. As the boats age, readiness will be an inevitable and growing challenge.

The Royal Navy has gone through this before. As Peter Hennessy and James Jinks point out in their reference work The Silent Deep, in the last few years of the UK’s first-generation Resolution-class SSBNs during the early 1990s, maintenance problems mounted and operational challenges grew. HMS Resolution reportedly conducted a 16-week-long patrol on one occasion, and one contingency apparently considered but never implemented included resupplying an SSBN with food at sea to allow an even more extended patrol.

The Resolutions were built with urgency and worked hard during the Cold War. But the Vanguards are now approaching similar ages and will be expected to serve longer than any other British nuclear-powered submarines.

The UK Ministry of Defence (MoD) insists that the successor Dreadnought programme is on track. However, in its last full report in 2018 on the submarine-building programme and other activities to support the strategic nuclear force, the National Audit Office noted that, although the MoD had improved management structures, some risks remain and ‘the coming years are crucial’.

The UK relies on one submarine-building yard at Barrow-in-Furness and one dock at Devonport for deep refit and refuelling. Currently, the programme to build the new Astute-class nuclear-powered attack submarines (SSNs) continues to be delayed. This could have a knock-on effect on the Dreadnought programme, which could itself ultimately affect plans for a successor SSN and the sustainability of the whole nuclear-powered submarine fleet. The delayed Vanguard LOP could push back planned refits for the rest of the class needed to keep them going during the coming decade. There have also been problems with shortages of key components causing delays.

Major investments are being made to modernise the UK’s submarine-building and nuclear-support infrastructure. But a report just published by the House of Commons Public Accounts Committee says these have also been hit by significant delays and cost increases. It all looks fragile to say the least, and room for manoeuvre remains limited should there be further problems.

Now, added to this are the challenges of COVID-19. In the short term, the navy is having to introduce additional precautions, including isolation periods, to protect the health of the crews and sustain the patrols, potentially putting added strain on a now much-reduced pool of submarine personnel. Overall submarine-personnel numbers have been cut significantly, as has crew provision for the SSBNs, since the end of the Cold War. However, the operational boats still need two crews to sustain the patrol cycle.

At the same time, the Barrow submarine yard has been operating at reduced levels for the last two months during the initial UK lockdown period. There may be a longer-term impact on the industrial base and supply chain.

The 50th anniversary of CASD in 2019 saw several high-profile events to mark a half-century of uninterrupted CASD operations – a significant feat given the resource levels throughout. Officially, CASD remains at the core of the UK’s nuclear posture. The current cost estimate for the Dreadnought programme is £31 billion (US$37bn) with a £10bn (US$12bn) contingency. Over this decade, it is estimated that 25% of the MoD’s equipment budget will be devoted to the submarine programmes (both Dreadnought and Astute) and supporting and modernising the strategic nuclear force. Even so, over the next few years, as it has been in the past, it may be a close-run thing to sustain that continuous at-sea presence.