AHC: Make other countries use the electoral college.

This has taken some time, but if I understand the Electoral College System (my knowledge is extremely limited) I think I can apply it to the United Kingdom

In the United Kingdom we have a multi-party system dominated by two main parties The Conservatives (Republicans) and Labour (Democrats). Most parties sitting in Westminster run in England, Wales and Scotland. Northern Ireland (NI) is an exception so I have not included it. Therefore the following applies to Great Britain (GB).

GB is divided in to Parliamentary Constituencies (Districts) and each constituency is represented by one Member of Parliament (MP). According to our Constitution a Prime Minister must command a majority in the House of Commons (House of Representatives). A majority equals half of the seats in the Commons (without NI) the number of available seats is 632 (total number of constituencies in GB) so a Party needs to secure at least 316 seats to win the legislature.  

Each region and each country is then appointed electors and this is where it gets a bit blah...So here is my formula (it's sort of based on the method of equal proportion)


The Prime Minister must secure at least 51% of the electoral votes in each region/country or 66 Electoral College Votes to win the keys to No.10. As in the US the Electors can either go with the popular vote or cast their votes on preference. If none of the candidates manage to get 66 votes then the leader of the largest party in the Commons will become Prime Minister. 



*(text) = closest equivalent 

That seems reasonablely close. But two questions: 1) how would this look like applied to a recent election  (Let's say the 2019 Federal Election in the UK) and 2) when and how could the UK/Great Britain implement this?