This is a nice thought but applying corporate manslaughter charges in this way within government would have a raft of unintended consequences.

The unfortunate reality is that governments have to make life and death decisions on a daily basis, so making it illegal for them to make decisions where more people will die would have a highly restrictive effect (examples below).

If a reallocation of NHS budget funding in the future causes an increase in a certain illness, could the chancellor be sued?

Could ministers be put in jail for smart motorways, where motorways have become more dangerous and cause more death in order to increase their capacity? (It was cheaper than doing a full widening)

Is it possible for a president to declare a war, or push the red button, without getting put behind bars?

There's a difference between policies that have unintended consequences, and simple incompetence, carelessness, or malice. I actually think heads of state should take a great deal more care when declaring wars, and Generals should take a lot more care in their prosecution - part of the humanitarian cost of essential legal immunity for heads of state is that a lot of wars are fought for essentially political reasons when a peaceful solution is absolutely possible, or the war itself serves no purpose. If the Blair administration had been put on trial for their actions in the run up to the Iraq war, for instance, there's no doubt that a reasonable court would frown upon the extent to which they mislead the public, and the disastrous effects of these efforts.

Maybe they would be found innocent, maybe not, but a depoliticized analysis of the extent to which they were culpable for the outcomes of their decisions would be very useful to the public at large.

In the case of the coronavirus response, the UK has double the death rate of similar nations (France, Germany), which are themselves not exemplars of a successful response. This is an extreme circumstance, on the level of a war, indeed worse than the second world war for british civilians, and it absolutely makes sense that people should be held accountable.

Can you name a recent prime minister who wouldn't have been found guilty under this law?

We have already argued for Blair and Boris.

Cameron was bombing hospitals so he’s going to go too…

It wouldn’t be manslaughter, but what about the windrush scandal? Maybe we could get May for that too.

Brown might be safe, is that it? All others behind bars?

In terms of COVID being worse than the Second World War for civilians I think this takes a very rosey perspective of the Second World War - for instance you are only counting “civilian” deaths but let’s not forget that there was a mandatory draft so the soldiers were effectively civilians with guns, and millions of our civilians were forced into the battlefield (but I guess we did have to sit around in our underwear and watch lots of Netflix). While each death is also a tragedy, I also think we have to take age into account, and appreciate that those young men in the battlefield had a lot more life left in them than the average COVID death.

I'm not really proposing a new law - just the application of existing laws about manslaughter to people who, historically, do a lot of it. Just because there are a lot of prime ministers that have fallen well short of any reasonable standard when it came to decisions that cost lives does not mean that we should continue to give governments carte blanche.

What you are describing is not a dysfunctional idea, but rather a dysfunctional system where there is no accountability. Boris Johnson can break the rules on donations (for example), pick an investigator for an 'independent investigation', and nobody will even mention the fact that it's a complete farce, because all the journalists are afraid of losing access.