For something I’m writing: Say that, through some masterly planned out bit of terrorism, a Hitler-esque night of murdering government officials takes place in modern-day Britain. Amongst the two victims are the Prime Minister, most members of the cabinet, and the queen, and the immediate heir. (Vaguely plausible in my world due to a combination of inside men, very large sums of money, and some supernatural psychic help).
As I understand it, if the Prime Minister abruptly kicks it, it’s the monarch’s perogative to effectively appoint a new head of government. But in my scenario, the queen and her successor are both dead, so obviously, the monarch’s not going to be doing any appointing.
Is this something that, say, the Queen could potentially have written into her will (eg, “in case of my untimely demise coinciding precisely with that of the prime minister, appoint John Doe”)? Would the majority party just sort of…decide, and pick someone? Would an election be held, and if so, would Parliament need to be dissolved (iirc, that’s required for an election)?
I understand that it’s a fairly far-out scenario, but I’m just looking for what more intelligent people than myself think would be most likely.
Bonus opinion question: If the Queen were to suddenly kick it, along with whoever’s next for the job, what are the chances of the institution of the monarchy suriviving?