Mark Galeotti makes an interesting point in this post on War on the Rocks titled Britain’s Nuclear Deterrent Isn’t a Military Asset, and Shouldn’t Be Funded as One.
The financial aspect of the argument is less interesting than the military point. Galeotti argues that two expensive projects, namely the two new aircraft carriers with accompanying F-35s and the nuclear deterrent, tie up so much of the defense budget that it causes disproportionate harm to other capabilities. If the nuclear deterrent were moved from the defense budget to some other post in the national budget, there would be more money left for other military projects. I lack the insight to see how this would be different from just increasing the defense budget, if the problem is that the national economy is sluggish.
But the military point is really good: Credible deterrence requires available assets that are relevant for the possible conflict scenarios. Nobody can imagine that the United Kingdom would use the Trident missiles in response to a limited military confrontation, so it is not a useful deterrent.
The British nuclear missiles are based on submarines, and the new Dreadnought-class, the replacement of the Vanguard-class, will be extremely expensive to build and maintain. They will be a valuable political instrument for the United Kingdom, but they will not be a replacement for other military assets.
So it comes down to the point that if the United Kingdom wants expensive military equipment to serve a specific political goal, they should acknowledge that there is a cost involved. Cutting the parts of the military that actually create deterrence is a really dumb strategy.