Have you ever watched any of the films or series which deal with designated survivor territory in some form or another? From Dave to Designated Survivor there are plenty of examples in fiction of this happening. They always filled me with intrigue but seemed sufficiently far from reality to not require me to delve too far into “what this would mean” in the UK context.

But now it’s official, we’re now in “designated survivor” territory. Boris Johnson, our Prime Minister, is in hospital in intensive care and Dominic Raab, the Foreign Secretary, is “deputising” for him.

The UK’s constitution does not really cover what should happen in this kind of situation. Our political system is not a presidential one, the Prime Minister is simply the leader of the largest party in the House of Commons. The Conservative Party currently has a large majority and so forms the government, which the Conservative Party’s leader then heads as Prime Minister. There is no formal deputy within our constitution to take over should Boris or become incapacitated. There is also no guidance in the Cabinet Manual covering this point, and little precedent.

In some ways it was perhaps easier for the Labour Party in the early 2000s. When Tony Blair had treatment for a heart condition, John Prescott stepped in for a few days. But he had been elected by the Labour Party to be its deputy Prime Minister, and voters broadly understood what this meant when they cast their ballots for Labour. This isn’t the same as having a formal constitutional role, but it perhaps helped justify Prescott deputising for a short period.

There’s no useful other historic precedent either. In June 1953 Churchill’s stroke was kept out of the newspapers and our public knowledge. The political practicalities and requirements were dealt with behind closed doors.

Poor Boris. The first Prime Minister we’ve only ever called by his first name and who, like him or loathe him, now feels like part of the UK’s furniture.

Of course I very much hope Boris recovers in the next few days. But if he doesn’t, what then?

Dominic Raab is – putting aside his Brexiteer tendencies – a competent politician who will undoubtedly have no difficulty in stepping into Boris’s shoes. He will have countless civil servants and advisors supporting him and no harm to the country will be done by not having Boris at the helm. Yet yesterday he confirmed that he does not have “prime ministerial responsibility” and decisions will currently need to be made collectively by the Cabinet. This has raised concerns about a “political vacuum”, e.g. in relation to issues of national security.

But if Boris does not recover, even with a large majority and a pandemic to be dealt with, some in the Conservative Party may have their knives ready to get out over the next few weeks. They may demand that a “new leader” be chosen from their ranks. I wouldn’t be at all surprised if this happens: there are too many senior Tory politicians with a deep thirst for power for it not to. But this would be catastrophic for the country right now, politically and economically but also for the public psyche. Amidst a Coronavirus pandemic we need confidence that our leaders are 100% focused on fighting the virus, not each other.

Let’s all hope Boris makes a full and swift recovery, so the wranglings of ambitious Tory MPs and the 1922 Committee (the Tory committee which elects its leaders) can remain silent.

But once Boris recovers and the country has also, we need to have a full and frank discussion about what this has all meant for our parliamentary democracy and our constitution. Unthinkable as the current situation was, it did happen. Which means we ought to plan for the future make sure as a country we are better equipped to deal with crisis situations. This includes thinking about whether our laws ought to include provisions for what happens if the Prime Minister is unable to act.

If we do deal with this point, then perhaps the very nature of what the Prime Minister’s role is has to change. We need to acknowledge and accept that the role has evolved considerably over the past 100 years. The Prime Minister has immense power, yet is not a formal constitutional role with the checks and balances of a presidential system. In order to protect our political and economic system, we need as a country to consider whether this is right. Maybe it would be more appropriate to include provisions in our laws for what a Prime Minister is and how someone takes over if he/she is ill or incapacitated – and who that someone should be.

In the meantime, recover soon Boris. For yourself, your family, the UK and ultimately for the stability of our political system.

This article was written morning of on 7 April but was updated to refer to statements made that evening and now links to a news story from 8 April on this same topic.