eli5 How can a political party in the uk win more seats than the votes they won?

Question

uk politics just makes no sense to me no matter how many times i get it explained by teachers. i know that first past the post leads to disproportionate votes but have never understood the system of winning seats

In: Other

Answer 1

Effectively, instead of one national election, you have several hundred local contests to elect one MP. In each constituency, the candidate with the largest number of votes wins the seat, regardless of how much they won by, what the turnout was, or even what the population of the constituency is (the boundaries are drawn up so they have roughly the same population, but there is substantial variation, and there are some outliers like the Western Isles with very small populations).

Consider a hypothetical election with 2 constituencies. In constituency 1, the Apple Party gets 3001 votes, the Banana Party gets 3000 votes, and the Coconut Party gets 100 votes. In constituency 2, the Coconut Party gets 8001 votes, the Banana Party gets 8000 votes, and the Apple Party doesn’t have a candidate. So the Apple Party wins constituency 1 and the Coconut Party wins constituency 2, even though the Banana Party got the most votes overall.

Now, the way it tends to work in practice is that the most popular party nationally gets heavily overrepresented. Parties that have strong support in certain regions, and no or little support elsewhere (like the SNP and the DUP) can also get heavily overrepresented. Parties whose support is spread thinly (like the Lib Dems, the Greens, and whichever far-right party is currently in vogue) tend to get heavily underrepresented.

But it’s worth remembering that, ultimately, a party’s political power is not determined by their number of seats. It’s determined by their ability to use those seats to get what they want. For example, the DUP have had a pretty consistent number of seats over the last couple of decades, but they were especially powerful in the 2017–19 Parliament because the Tories were just short of a majority and the DUP were able to help them win votes on various matters.