The potential fall-out from the UK vote to leave the EU cannot be over-estimated. The political, economic and constitutional implications are deeply uncertain. The market turmoil and the plunge in the value of the pound will translate into massive financial pressures on government spending. The pressures for constitutional referenda in Scotland and Northern Ireland have just strengthened dramatically. Political parties in the UK are now preparing for a General Election in the next few months as an inevitable response to the perfect storm of an unelected Prime Minister and a new Chancellor negotiating departure from the EU with majority opposition to Brexit in Parliament.
We will see major additional cuts in public spending over the coming months, the only question is how big and whether they will be sufficient to steady confidence in the deficit. The government will be under huge financial pressure to suspend major project investments as officials reassess the ability to pay. Government departments will be working overtime in the coming weeks under instruction from the Treasury to find savings quickly.
This is not the environment for an early smooth decision to move forward on Trident. Like Emily Thornberry's rapid move to postpone the Labour Party's policy review, the government will be suspending any plans they may have had to take this to a vote this summer.
But where does this leave Britain's foreign and defence policy, and the role of its nuclear arsenal within it?
Of course there will be much speculation over what was behind this vote - obviously a scepticism over the European project, fears over migration and a disaffection with 'the establishment'. But there is also a deep attachment to nationalistic sentiments that are difficult to counter and which were encouraged by many in the Remain camp ('Britain Stronger in Europe'). Pride in Britain's ability to stand alone will tend to play strongly in favour of investing in the next generation of nuclear weapons, whatever the cost. There is even an argument that Britain out of Europe needs nuclear weapons all the more as a symbol of its independence, or its relationship with the United States and NATO.
On the other hand, similar considerations apply to other forms of defence spending, already under pressure from the allocation of a third of the defence procurement budget to the Trident renewal project over the next 15 years. Difficult choices have not yet been faced within MoD, whose plan relies upon a growth in GDP that will be reversed in the coming months and years. Those difficult choices may be even more acute as a result of this national decision yesterday. Will this therefore mean a significantly higher commitment than to spend 2% of GDP?
It may be that significantly cheaper alternative nuclear weapon systems (and they do exist, whatever the erroneous claims of parliamentarians attached to the current posture may be) will become attractive options. If there are any messages in this referendum, one is to be aware that people are more prepared than ever to think the unthinkable and to challenge received wisdom.
Whilst this decision will confirm my previous predictions that the Trident vote will not be taken this summer, and could be delayed until the resolution of uncertainty over elections and leaderships much later in 2016 or in 2017, it is unlikely to result in a Parliamentary majority against continuing with the project at this stage. But as with all other things, uncertainties have just risen dramatically, events over the coming months could decisively change the balance of probabilities, and predictions made today could be premature.