It’s good advice in life to try and find yourself something that you are as passionate and excited about as Jo Swinson, the leader of Britain’s Liberal Democrats, is, about pushing the nuclear button and causing a nuclear holocaust:

What’s remarkable about that response isn’t the “yes” – it’s the sheer enthusiasm she has for it. She barely waits until the question is asked, and she seems tremendously jolly at the prospect. Well, she is an environmentalist at heart, and if there’s one thing greens love, it’s the idea of cutting the human population. Swinson’s just found the fastest way to do it. Instantaneous, relatively painless if you’re in the blast zone, and sure to obtain international co-operation from others in response, cutting the population of Britain at the same time as she cuts the population of whatever country she doesn’t like on a Tuesday.

Jokes aside, it’s a strange one. On the practicalities, Swinson is absolutely right to give that answer. Whether you agree with nuclear weapons or not, there’s not much point having them, and they lose all deterrent effect, if the enemies of your country don’t think that you would ever use them. “We should have no nuclear weapons at all” is a perfectly logical position. So is “we should have them and be prepared to use them”. Having them, but promising never to use them? That’s just a waste of money.

One of the first jobs of a new UK Prime Minister is to write the four “letters of last resort”. These are instructions, in a sealed envelope, to the four commanding officers of the UK’s four nuclear submarines, telling them what to do if London has been destroyed and the UK Government no longer exists. Essentially there are two potential orders: Surrender, or “nuke the bastards who did this”. Nobody knows what instructions are in those letters, and hopefully, nobody will ever need to know. The point of them, and the point of the weapons themselves, is to deter anyone from attacking the UK with Nuclear Weapons, because the UK’s own weapons are at sea, and can be deployed well after the country itself has been destroyed, with an order from an already-dead Prime Minister.

It is, in fact, hard to imagine any circumstances in which the UK’s nuclear weapons would be used while the Prime Minister was still alive. So essentially, Swinson is telling us what she’d write in her letter – and it makes sense.

And what of the other two? Well, Johnson has no ideological opposition to nukes, but Corbyn? Let’s face it: He’s not going to write an order telling his commanders to nuke people if he’s dead, is he? Not unless he can blame America and Israel, anyway….

For your enjoyment, if you’ve never seen it, here is “Yes Prime Minister” on the futility of the question about whether the button would ever be pushed: