A British Prime Minister from the House of Lords...

[AuH2O Republican]

I am going to start writing some kind of fiction soon, regarding a modern day scenario where the governing Conservative Party caucus (not the party membership) selects a Lord to become leader and, therefore, Prime Minister. There would have been no provision in the Peerage Act 1963 to allow members of the Lords to disclaim hereditary peerages.

Is anyone here able to help me in clarifying how exactly a government can be formed in this scenario? I'm sure there is something in a Trollope novel somewhere but I thought this would be my first port of call.

My understanding is that the Queen's Speech has to get through the Commons, so as long as there is a majority in that chamber, a government can be formed.

Hopefully someone with a little more knowledge of British constitutional procedure may be able to correct me if I'm wrong.

[Filuwaúrdjan]

He/she would have to resign their seat in the Lords and run in a by-election for a seat in the Commons, as happened with Alec Douglas-Hume in 1963.

[IceAgeComing]

and if they couldn't do that as in the scenario in the OP then they would very quickly change the law to let them resign - that's basically why the Peerage Act was passed in the first place...

[MASHED POTATOES. VOTE!]

I believe it is considered acceptable for a caretaker Prime Minister to come from the Lords, but nothing beyond that.

Decades before RL Peerage Act it became a convention that the PM should sit in the Commons. That's one of the reasons (aside of him being an insufferable ass) Curzon was passed over to succeed Bonar Law. Halifax's premiership was a real possibility in 1940, but it was agreed a bill would have to be passed to allow him to sit in the Commons as a matter of practicality. Halifax, not keen on taking the job, used the "can't govern from the lords" excuse to step aside.

[Filuwaúrdjan]

I believe it is considered acceptable for a caretaker Prime Minister to come from the Lords, but nothing beyond that.

What is considered acceptable is whatever is considered acceptable. I doubt even that would be considered acceptable in 2017.

[MASHED POTATOES. VOTE!]

I believe it is considered acceptable for a caretaker Prime Minister to come from the Lords, but nothing beyond that.

What is considered acceptable is whatever is considered acceptable. I doubt even that would be considered acceptable in 2017.

Practically no.

[Gary J]

There is no legal provision preventing a Prime Minister being in the House of Lords. It is however a political necessity that a modern Prime Minister either be a member of the House of Commons or become one soon after appointment.