If recent reportage is to be believed, US President Donald Trump plans to build a ‘Golden Dome’ missile defence shield to monitor potential enemy threats to the USA and US interests around the world. It is speculated that the cutting-edge defence structure, which is likely to cost hundreds of billions of dollars, could be in place and up and running as early as 2026.

The name itself tips a hat to Israel’s sophisticated multi-layered air defence system against ballistic and cruise missiles and drone attacks. Popularly known as ‘Iron Dome’, it actually consists of three different but coordinated systems; first there are the long-range Arrow-2 and Arrow-3 interceptors, designed to engage threats in and outside the atmosphere respectively.

This is backed up by the mid-range ‘David's Sling’ system, designed to shoot down ballistic missiles fired from 100 to 200 kilometres away. And finally there is the ‘Iron Dome’ proper, a short-range system built to intercept the kind of rockets fired by Hamas in Gaza and Hezbollah in Lebanon.

But there are fundamental differences in scale and technology in the proposed US system. According to sources, Elon Musk's SpaceX company is partnering with software maker Palantir and drone builder Anduril to build it.

SpaceX's involvement in the project, which some say might cost around $10 billion, would include building and launching more than 1,000 satellites around the globe to sense missiles and track their movements.

These would be supported by around 200 attack satellites armed with precision missiles or lasers would then bring down threatening enemy missiles. A true ‘sense and shoot’ system.

The decision process is still in its early days, but the Pentagon is suggesting that parts of the Golden Dome could be operational from next year, with other parts delivered in the period up to 2030. It’s ambitious in both its technology and global reach, but they may just pull it off.

Should the UK also be considering some sort of ‘British Dome’ to protect against similar threats? The stark reality is that the UK has no credible air defence systems that even approach the Israeli capability, let along the US initiative.

It is true that HMS Diamond managed to shoot down a Houthi anti-ship ballistic missile in the Red Sea recently, but that was a one-off, and the Royal Navy is now scrambling to update the rest of its T45 destroyers with an appropriate capability. And until the Strategic Defence Review reports in the next couple of months – hopefully – we have no idea where the money to do so might come from.

Now, it’s true that the threat of a ballistic missile attack against the UK at the moment is probably minimal. But all defence planning is hypothetical until you’re actually involved in a war, so let’s just look at where British national interests might be vulnerable.

Top of the list must be Cyprus, where Britain maintains two sovereign base areas at Akrotiri and Dhekelia. The former is the location of the RAF base critical for operations across the Middle East, while the latter has the joint GCHQ/NSA signals intelligence listening station at Ayios Nikolaos.

Both are within range of Iran’s long-range ballistic missiles and also of those which might be launched by its proxies in Iran, Lebanon, Syria, and Iraq. They have no permanent anti-ballistic missile defence (ABMD) provision.

Then there are various other strategic locations around the globe which are vital UK interests – Gibraltar, the Falklands, Diego Garcia, and Brunei to name but a few. All are vulnerable to submarine-launched or air-launched ballistic missile attack, and none have ABMD.

And what about the UK itself? Surely the capital, London, is appropriately defended, and also the independent nuclear deterrent submarine base at Faslane on the Clyde?

The answer is no. You could argue that London could be defended by stationing a T45 destroyer on the Thames, and that Faslane could be likewise protected by another stationed in the Firth of Clyde, but Britain’s has only six T45 destroyers and they have many other tasks too – and so it could be that the rest of the UK’s national interests would be undefended.

This state of affairs is not very satisfactory, hence the cries from the usual suspects that “something must be done”. But what, and how is it going to be paid for? The UK defence budget cannot cope with present demands as it is.

So, are we likely to see the UK adopt a ‘British Dome’? Unlikely I would say, but until we come up with something Britain and its interests are wide open to ballistic missile attack.

And that is not something that our potential enemies will have failed to notice.

Lt Col Stuart Crawford is a political and defence commentator and former army officer. Sign up for his podcasts and newsletters at www.DefenceReview.uk