I have reposted below an article I wrote for Conservative Home. I also have a strong interest in defence issues (not just planning & the Isle of Dogs).

http://www.conservativehome.com/platform/2016/11/andrew-wood-we-cant-keep-running-down-the-navy-by-stealth-and-pretending-that-nothing-has-changed.html 

From the end of 2018, for an underdetermined period of time, the Royal Navy’s ships will no longer be capable of sinking or even heavily damaging enemy warships at a safe distance. (The Royal Air Force have not had that ability since the year 2000 when the Sea Eagle missile was retired.)  The announcement was made last week that the Harpoon anti-ship missile will go out of service at the end of 2018.
Harpoon is a missile with a range of around 120 kilometres.  It is designed to sink ships – and is still in production and very widely used around the world from ships, submarines or air launched. Most of the countries that have it intend to use Harpoon for the foreseeable future, although newer missiles now surpass it in range, speed and lethality.  It currently equips all 13 Type 23 frigates and three out of six Type 45 destroyers (that only half are so equipped is another capability gap).
From early next year the Sea Skua, a helicopter-launched anti-surface vessel missile, will also go out of service. Its replacement, Sea Venom, will arrive in 2020.  But with a warhead weight of only 30 kg, it is designed to sink only smaller vessels, and is not capable of doing so to larger ones.
Our navy is almost unique in losing anti-ship capabilities. In fact, many navies are starting to invest in new and more capable missiles. The Norwegians have the New Strike Missile; the Germans are buying the RBS-15; the Swedes have just re-launched their ground-based anti-ship missile units. The Indians have Brahmos, with a range of 300 kilometers (soon to be 600km): the kinetic impact alone of hitting a target at its speed of Mach 3 would be enough to sink most ships. It is far more lethal & longer-ranged than Harpoon.
The Americans, who also rely on Harpoon, now have several active programmes to upgrade their anti-ship missile capability, and are even upgrading their premier anti-air missile with a back-up anti-ship capability.
There is as yet no funded UK replacement programme for Harpoon, although the Government announced last year that we are working with France on a future cruise anti-ship weapon that could replace it. Even more worryingly, the latest announcements about the new Type 26 frigates make no mention of the Mk 41 vertical launch system which could hold any future offensive missile.
The only funded research programme with a decent range and decent survivability is the air-launched Spear 3 missile ,which should be available in the early 2020’s from F-35B fighter jets. But with a total missile weight of 110 kg, it again lacks lethality (although multiple missile strikes could disable enemy warships). The Norwegians by contrast have invested in upgrading their anti-ship missile to be air-launched from F-35s.
The only decent anti-ship capability we will have left are Spearfish submarine torpedoes.  Torpedoes are certainly capable of sinking ships – as in the case of Argentina’s General Belgrano during the Falklands War – but they have neither the range nor the speed of response of missiles, and we only have seven submarines dedicated to killing enemy vessels. Against capable enemy warships they would have to get much closer than the maximum range of 54 kilometers before attacking.
We have in recent years cut military capabilities, and the inability of Royal Navy ships to take out enemy ships, except by using their main guns at short range or ramming them, is a serious loss of capacity. It is true that Daesh has no ships – but even Hezbollah has ground-launched anti-ship missiles. Our allies retain, or are increasing, their anti-ship capabilities so, arguably, the loss is not serious at a NATO level.  But at a national level it is.
In 1919, we declared a ten year rule “on the assumption that the British Empire would not be engaged in any great war during the next ten years” that we could reduce military investment: the rule lasted until 1932. The reality is that during recent years we have unofficially done the same.  We are not fully equipping our military to fight a well-equipped enemy, and what investment there has been has left the military without a full range of options. For example, the Type 45 & Type 26 ships do not have any ship-launched anti-submarine torpedo tubes, unlike their predecessors.  While the Government could reverse this decision, the reality is that without an increase in funding this will probably result in a “capability holiday” somewhere else.
We have three options.  First, to make it clear that we are undertaking a modern version of the ten-year rule which may constrain our foreign policy options. Second, to admit that alone and in isolation that we are no longer capable of fighting a peer level adversary across the full range of capabilities, that we can only do so in alliance with other nations, and that we will start to plan on that basis.
Or, third, rather then salami-slice, cut whole areas of capability in order to focus on the remaining core ones – for example, the ability to land the Royal Marines on enemy shores, or our ability to launch a brigade-sized air assault. I recommend neither, but at least this third option might allow us to focus better on those areas of capability that we wish to retain. It is time to start having these conversations, rather than pretending we can have our cake and eat it.