Why a submarine-based nuclear deterrent is the best choice for the UK

This piece was inspired by a recent click-bait gem that proposes the UK consider joining the US Long-Range Strike-Bomber (LRS-B) programme with a view to replacing the submarine-launched nuclear deterrent with an air-launched alternative. This kind of proposal rears its ugly head very so often and was even briefly enshrined in UKIP defence policy. Here we will show why submarines are overwhelmingly the best vehicle to carry the UK nuclear deterrent.

The ocean is the ultimate hiding place

As the marvellous Vulcan bomber display aircraft flies for the last time, many misty-eyed aviation enthusiasts hanker for a return of the Cold War ‘glory days’ of the RAF V-Force. Graceful British-built giants lined up on an airfield where mustachioed chaps await the ‘scramble’, fervently hoping not to have to make the mad dash to get airborne before this corner of Lincolnshire is blasted to ashes.

The submarine-launched deterrent that replaced the V-Force in 1969 is decidedly less glamorous, virtually invisible to the public but thankfully much more secure. Airbases are inherently vulnerable to pre-emptive strikes either conventional or nuclear, especially from precision cruise or ballistic missiles that could, for example be launched from submarines. Either some of the UK deterrent-carrying aircraft would have to be kept airborne or the airbase must hope it can stay safe behind a costly and complex array of air defences. In contrast the submarine loitering in the deep ocean that covers two-thirds of the globe is secure, safely cloaked by several hundred feet of water, its exact location known only to a few of men onboard.

Some have claimed that SSBNs are becoming easier to detect in an age of ultra-quiet conventional submarines, UUVs and sonars linked to supercomputers. There maybe some truth in this, but submarine quieting technology is also evolving. The complex thermal layers and background noise of the ocean always provide hiding places where the SSBN can disappear. An SSBN is not obliged to be on the offensive like a hunting SSN/SSK or warship, instead it can cruise quietly at minimum speed in places where it is hardest to find. The RN claims that its ballistic submarines have never been detected. This claim maybe impossible to verify but in general, a well-handled submarine is an exceptionally stealthy weapons platform.

Aircraft fly for hours, submarines patrol for months

A single submarine somewhere under the ocean can maintain an effective deterrent for months on end before handing over to another sub. With just 4 submarines, this deterrence has been faithfully maintained by the RN for 46 years. An aircraft mission can be measured in hours and if credible deterrence requires even just one aircraft to be airborne at all times, this would require a large number of aircrew and aircraft kept at readiness. An even bigger problem is the increased chance of accidents that accompany the continual take off and landings of aircraft carrying nuclear weapons. The carefully choreographed road and rail transport of nuclear materials around the UK is already highly controversial. Nuclear-armed aircraft flying daily in UK airspace would be even less welcome. Would the aircraft aimlessly circle over the North Sea, before conducting AAR then heading off to their target when called upon?

The global reach of the ballistic missile submarine

Trident D5 missiles have a range of around 4,000 nautical miles, this allows great flexibility in where the SSBN is deployed and with the submarine’s mobility allows it to threaten just about anywhere on the planet. Although in theory an aircraft can respond more quickly to reach very distant targets, it may have to traverse foreign airspace with all the complications that may involve. It may also require in-flight refuelling, another complication requiring multiple aircraft and extensive pre-planning.

The true stealth aircraft many never exist

Every military aircraft designer dreams of creating an aeroplane entirely undetectable by radar. After expending vast sums of money and building up years of experience in secret ‘black’ projects the US partially achieved this goal with the B-2, the F-117, the F-22 and the F-35 (sort of). Although much harder to detect by radar than conventional aircraft, they cannot be made entirely invisible. An F-117 was detected and shot down in as far back as 1999 over Serbia using relatively crude Soviet designed radars. Although difficult to quantify, it is almost certain that modern Chinese and Russian air defence radars can detect modern ‘stealth’ aircraft under certain conditions. In board terms, development of radar is likely to outpace development of stealth aircraft in future. The coatings and aerodynamic design required to reduce radar returns result in serious compromises in capability, lengthening development schedules and grossly inflating costs. Even if the LRS-B makes it off the drawing board, by the time it’s in service a new generations of radars will almost certainly render it vulnerable. Only by attacking in overwhelming numbers could there be a guarantee that the nuclear weapon could be delivered to the target protected by modern integrated air defence systems. A ballistic missile with multiple warheads (such as Trident) descending steeply at many times the speed of sound from the upper atmosphere is an exceptionally difficult target for interception, being smaller, faster and arriving with less warning than either a bomber or a stand-off cruise missile.

The deep strike agenda

Apart from restoring some prestige and purpose to the RAF, a supposed benefit of a UK long-range bomber would be the option to use them in the conventional bombing role. The SSBN has a single purpose and offers no other capability. This often seen as a drawback but there can be no doubt that there is always an SSBN on patrol and the deterrent remains continuous. Would the multi-role bombers be able to maintain the deterrent while assigned to other tasks? Could the detection of the bomber on a conventional mission could be mis-interpreted as a nuclear strike and trigger a nuclear conflict?

If we assume these issues could be overcome, there is some merit in the UK having a long-range bomber but are there better options? Many strike missions could be better done by upgrading our aircraft carriers (with CATOBAR) and expanding the type of aircraft they could carry including future long-range UAVs such as the US Navy’s UCLASS. Equipping our surface fleet with large batteries of Tomahawk Land Attack Missiles would also increase our global reach in a way that the bomber could struggle to match constrained by over-flight, refuelling and endurance issues.

Cost miscalculations

The US Air Force says the price tag of a single LRS-B will be around half a billion dollars when the first are delivered around 2030. It would be easy to fall into the trap of taking the guide price for Trident Successor submarines of around £25Bn and concluding we could buy up to 30 LRS-B with change to spare. Major defence projects in the US and UK have a dismal recent history of cost inflation. The Trident successor submarines may suffer from this, although SSBN construction is complex the successor project should be relatively low risk, utilising much of the existing Astute Class design and sharing the common missile compartment with US submarines. Major aerospace projects tend to be even worse offenders. (Witness the Eurofighter Typhoon or the F-35.) The current eye-watering $550M price for the LRS-B will be probably prove to be a gross under-estimate.

The supporting infrastructure already exists for Trident submarines. The Faslane base and weapon handling facilities at Coulport are already in place and paid for. Any new bomber would require pricey new airfield facilities and nuclear weapon infrastructure to be built from scratch, presumably in East Anglia. This is before the cost of new air defence systems to protect the airfields is added.

The RN benefits from over 40 years of accumulated experience in SSBN operations with a training pipeline in place and ready to make the transition to the successor submarines. In contrast the RAF would be starting virtually from scratch, not having operated a heavy bomber since the mid-1980s. It would have to recruit and train a large number of aircrew and support staff, another lengthy and expensive project.

Finally, tying the future of the UK deterrent to the LRS-B would be very high risk. The USAF has a history of large bomber projects that have been cancelled. In an era of constrained budgets, there maybe a struggle to fund both the Ohio class SSBN replacements (SSBN-X) as well as a very expensive bomber programme (even if the main USAF interest is in conventional strike). The US wisely regards its SSBNs as the most important part of its nuclear triad and SSBN-X will likely be given the appropriate priority.