Minority Governments and the Boundary Commission

@edentelection general election politics uk · 7 comments · 500 words

The UK is almost certain to have a General Election this year⁰. The Boundary Commission for England¹ has reworked the existing Parliamentary constituencies to make them more fair².

As such, constituencies are generally more equal in terms of electorate. But, of course, geography trumps geometry. So the Isle of Wight now has two constituencies of 56k and 54k, whereas the average constituency has 73k.

I wanted to know if these new boundaries meant that a political party could win the majority of votes, but still not get a majority of seats³. So I downloaded the data.

There are 650 seats in The UK. Obviously, if 649 of them had turnouts of 3 people - 2 voting for Party X and 1 for Party Y - and the last seat had 74k people vote for Y, then X wins with a minority of the national vote. But let's go for something more realistic.

The total electorate is 47,558,348⁴. Therefore, a party would need 23,779,175 votes to win a national majority.

If Party X won 100% of the vote in the most populous 316 constituencies, they'd have 23,844,185 votes. If Party Y won 100% of the vote in the remaining 334 constituencies, they'd have 23,714,163 votes.

So, yes, it is technically⁵ possible for a political party to win the majority of votes but still not win the majority of seats. In fact, a party could win 24,322,616 votes (51.1%) and still be one seat short of a plurality.

But what about…?

Is this probable? No. Even in the wildest fantasies of party faithful, no one is winning 100% of the vote in any constituency. England, Scotland, Wales, and NI each have their own political parties and vastly different electorate.

But is it possible? Yes. If Party X won the 326 least-populous seats with 100% of the vote, they would have a majority in Parliament yet only have 48.6% of the popular vote.

Personally, I think Rishi will hold it in January 2025. Clinging on to power until the very last second, hoping something will happen that will change his fortune. ↩︎
The UK is a country of four countries. Yes, it is complicated. No, I won't explain it. ↩︎
Yes, I know your favourite MP has been done dirty by these changes. No, I don't think there are political shenanigans afoot targeting specific MPs. ↩︎
The UK's "First Past The Post" system means that the national vote share is often wildly different to the number of seats won. But I'm unaware of an election where a party won the most votes but didn't take the most seats. ↩︎
The Office for National Statistics says "In December 2021, there were 46,560,452 Parliamentary electoral registrations" - but let's not quibble. ↩︎
The best kind of possible! ↩︎

7 thoughts on “Minority Governments and the Boundary Commission”

2024-02-20 13:13

Simon Wood said on mastodon.social:

@Edent Re: footnote 4. 1951 Labour won the popular vote by 48.8% to 48% but the Conservatives won a majority. Feb 1974 the Conservatives had 37.9% to Labour’s 37.2% but Labour won the most seats (albeit not enough for a majority).
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2024-02-20 13:40

Sam says:

When was the last time in the UK that a government won won a majority of votes? 1931? PS: what do you think of the idea of an MPs vote in parliament being weighted by the number of votes they received.
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1. 2024-02-20 14:41
  
  @edent says:
  
  I think that quickly descends into tyranny of the majority if the "largest" MPs form a caucus. There is no perfect system. But attempts to tweak often fail in interesting ways unless they've been robustly tested.
  Reply
2024-02-20 13:40

Jeremy GH says:

According to the "full report" downlodable from UK Election Statistics: 1918-2023: A century of elections (https://commonslibrary.parliament.uk/research-briefings/cbp-7529/), there have been three general elections in the last century when the party with most votes did not win a majority of seats: 1929, 1951 and Feb 1974. The Electoral Calculus website has, at https://www.electoralcalculus.co.uk/flatfile.html a full set of GE results for anyone who wants to play around, and work out the minimum proportion of votes needed to have obtained a majority of seats, and how (un)realistic that might be - depending on how you might define realism. Given the "objective" of winning a majority of seats (326) with minimum number of votes: in 2019 the 326 MPs with lowest number of votes cast for them, had (between them) less than 22% of the total votes cast.
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2024-02-20 13:51

Simon Lucy said on mastodon.social:

@Edent This is a deal saner than most of what's written on representation and the UK Parliament. The points about both the Four Nations and the geographical distribution are well made.
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2024-02-20 14:05

bovine3dom said on masto.ai:

@Edent you can do better if you want to waste the most votes for one party and allocate the other party's vote as efficiently as possible. E.g. give all the votes in half-1 of the constituencies to the inefficient party, then 49.9% of the votes in all the other constituencies to them with 50.1% going to the efficient party. You end up with ~75% of the total votes going to the losing party and the winner only getting ~25% of the votes
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2024-02-21 14:30

Andrew Ross says:

(American looks at the Electoral College and laughs ruefully)
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7 thoughts on “Minority Governments and the Boundary Commission”

Simon Wood said on mastodon.social:

Sam says:

@edent says:

Jeremy GH says:

Simon Lucy said on mastodon.social:

bovine3dom said on masto.ai:

Andrew Ross says:

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