Trident – is Theresa May a better deterrent?

One of the first decisions Theresa May made on becoming Prime Minister after the Brexit referendum was to approve the manufacture of four replacement submarines for our Trident nuclear weapons system.  She argued that it would be an “act of gross irresponsibility” for the UK to abandon the continuous-at-sea weapons system, continuing the logic that a submarine which cannot be traced is an invisible force for retribution which would deter an aggressor.

I’ll pass on the issue of whether or not we should have nuclear weapons.  That’s a different and important point to argue.  What I’d like to highlight here is that whilst the concept that a nuclear submarine was undetectable may have been valid in the 1960s, it’s no longer the case.  The countries that signed up to the principle of Mutually Assured Destruction now have the technology to know exactly where each other’s submarines are.  So what is Trident meant to be protecting us from?

Ever since the cold war, when the military brass came up with the idea of spending billions hiding nuclear missiles in submarines, they’ve also been spending billions on developing techniques to work out where their enemies’ submarines are.  If they could do that, so their logic goes, they could nuke those submarines as part of their pre-emptive strike and live happy, if paranoid, lives ever after.  The first the general public heard of any of this was probably in the film “The Hunt for Red October”.  Although that was fiction, facts about submarine tracking began to appear in 1987, when the US Senate threatened to ban Toshiba from selling any of their products in the US after it emerged that a Norwegian company had sold Toshiba’s high precision milling machines to Russia.

The connection between improved metal milling and tracking submarines is that submarines are generally located by the noise they make.  Their propellers generate cavitation bubbles as they drive through the water, producing a very characteristic sound which is specific for each propeller and can even be used to identify individual submarines.  The more accurately you can machine the propeller, the quieter the submarine becomes, and the more difficult it is to detect.  Until the mid 1980s, US submarines were far quieter, but at that point they noticed a new generation of soviet subs, which were far more difficult to find.  Various countries were blamed for selling the Russians better technology, but Toshiba got the short straw and was vilified in the US, with a group of Republican senators going as far as staging a public smashing of a Toshiba stereo.  It meant that the affair became front page news, with the public learning for the first time that it might actually be possible to track a nuclear submarine.


Most military technology which involves hiding something is a cat and mouse game, where countries try to outwit each other in a technical rat race.  For the past fifty years, every nation with a submarine fleet has been developing hydrophones – underwater audio sensors which pick up the characteristic noise that submarines make.  They get towed behind ships and are deployed in underwater arrays to try and track enemy submarines.  As hydrophones became more sensitive, submarine designers tried to combat this by making quieter submarines, even dispensing with propellers and replacing them with propulsors and direct drive electric motors.  That means that nuclear submarines have still been able to hide, for at least some of their time at sea.

In the last decade the technology equation between stealth and detection has started to become unbalanced, moving in favour of the trackers.  The reason for that comes from the concentration of work that is happening in smartphones and the IoT.  Sensors work by detecting a signal, usually by some mechanical means, then amplifying it.  Further information can be extracted by gathering information from multiple sensors and analysing the collection of signals.  The explosive growth of smartphones has galvanised research and development in sensors and the accompanying data analytics.  They’ve become smaller and as a result can often be much more sensitive, producing a far larger signal in relation to the background noise.  At the same time the data analytics which is being developed for IoT applications is able to extract almost invisible levels of information from arrays of sensors.

Both of those developments have been taken on board by hydrophone designers.  A few decades ago, hydrophone arrays were mostly used to detect threats – either trying to detect a submarine approaching a landmass or harbour, a submarine listening for nearby ships, or vice versa.  Ranges were tens or hundreds of miles.  That has changed.  Recently I’ve heard that hydrophone arrays off the US East Coast can detect a Trident nuclear submarine going in out of its Faslane base in Scotland, over 3,000 miles away.  Not only that, they can allegedly tell which submarine it is.  Hydrophones are also becoming far more mobile.  An article in New Scientist earlier this year described the development of flocks of solar powered drones and gliders, which can dip in and out of the sea to track submarines.  Both China and the US have talked about their capabilities in this field and it’s almost certain that every other country with a major naval presence has them as well.

The problem for submarines is that making them harder to detect is difficult.  It involves mechanical engineering which takes a lot of time – typically years.  In contrast, the development of sensors and analytics is following a consumer electronics cadence, with advances every year.  That makes it an unequal race, where the submarine is going to lose.  By the time that the UK’s new Trident submarines go to sea, everyone who is interested will know exactly where they are.  Tracking them will probably be within the capability of the maker community.  We might even see crowdfunded tracking projects.

So why did 472 MPs vote to spend £31 billion on renewing a defence system whose raison d’être is out of date?  For some it was probably about defence jobs; for other, PR to help reassure our NATO allies after the Brexit result.  But many probably still believe in the principle of retribution enshrined in the concept of Mutually Assured Destruction.

One of Theresa May’s first tasks on taking office will have been to write a letter.  That letter of last resort is given to the Trident submarine commanders and directs them what to do if they discover that the UK has been destroyed in a nuclear attack.  We don’t know what those instructions are.  They remain secret, but the assumption is that the letter contains a command to retaliate, triggering a devastating attack on the country which perpetrated the attack.  There may be other options, such as sailing to Australia to hand over the submarine and retiring to Bondi Beach.  David Greig’s brilliant play “The Letter of Last Resort”, which you can read online here, provides some highly entertaining options.  But I digress.

There are two important points about this policy of mutually assured destruction:

  1. The first is that an aggressor doesn’t know where the submarines are. If they do, then they can target them in their pre-emptive nuclear strike.  If they can do that, the deterrent is worthless.  And we now know that the major nuclear powers can do exactly that.
  2. The second is that the aggressor is worried about a nuclear response.

Once we assume that major nuclear powers can wipe out our Trident submarines as part of their nuclear onslaught, then our concerns should focus on regimes which don’t care too much about getting themselves wiped out.  North Korea is one, but we’re probably not top of their list of target countries.  They’ll run out of warheads hitting South Korea and Japan.  That leaves the major threat as Jihadi states, who could see annihilation as a country-wide opportunity to get to paradise fast with the added benefit of multiple virgins.

In which case, there might be a cheaper defence policy option.  Rather than an expensive fleet of submarines, we could deploy some land based missiles spread around the country.  All we need as a deterrent is to keep Theresa May (or Andrea Leadsom, Amber Rudd, or even Dianne Abbott) as our Prime Minister with her finger firmly on the red button.  For if a Jihadi is killed by a woman, they don’t get any virgins in Paradise.  It’s a simple and effective alternative, which could save us £31 billion.  The US electorate might also find that a compellingly persuasive reason to vote for Hilary.

Of course, like the fictitious belief that nuclear submarines can’t be tracked, the idea that a Jihadi killed by a woman doesn’t go to Paradise is also fiction, in this case dreamt up, or at least propagated by another publicity hungry US Republican senator – Ed Royce.  But if we’re going to base our defence strategy and spending on fiction, it’s a much cheaper and more appealing story.  In a “post-truth” political age, maybe we should just go for the better stories.  Especially if they’re cheap.  After all, with the pound falling on the foreign exchange markets, the Government needs to save every penny it can.