A question for you Ukers:
What would have happened if the Conservatives had won a majority of the seats of Parliament, but Theresa May lost her own seat?
The Tories would then hold a leadership election - their MP’s vote for the leader of their party (IIRC). Usually the PM is in one of the safest seats in the country - can’t recall a PM ever losing their own seat - but could happen…
From 2010 (but still applies) - http://news.bbc.co.uk/1/hi/uk_politics/election_2010/8497014.stm#lose
Labour members (any member of the public who signs up to join the Labour Party can vote on the leader)
Sorry mate - I’ve no idea on the other parties’ leaders how how they elect them.