It's often said in UK politics that the Conservatives usually require a 7 percent lead in the popular vote to gain an overall majority of seats in the House of Commons; but the Labour party can get a majority with practically no lead at all (indeed it's not inconceivable that the Conservatives could have a small plurality of votes and Labour still have a majority of seats).

How is this possible?

I know that people tend to spread out from the centres of the towns and cities, but surely that would effect Labour more than it does the Conservatives, who seem to have strong rural constituencies.

Additionally, is this a UK phenomena or does is effect Westminster systems everywhere?

  • it can happen in other single member plurality district systems. in 2012, House Republicans received fewer votes than House Democrats, but retained a majority
    – Publius
    Commented Oct 21, 2014 at 3:45
  • The basic reason in the UK is that redefining the boundaries of electoral constituencies lags behind the movement of the population, often by several years. Urban constituencies which tend to vote Labour therefore tend to have a smaller electorate than rural constituencies which tend to vote Conservative. Since redefining the boundaries requires parliamentary legislation, there may be no incentive for the government to correct this "problem" - for example the Blair and Brown Labour governments from 1997-2010 never attempted to correct it.
    – alephzero
    Commented Jun 11, 2017 at 4:49
  • ... and the Conservative/Liberal coalition of 2010-2015 tried and failed, because the Liberal leader insisted on pursuing his party's policies to introduce proportional representation as part of the coalition deal, That policy was decisively rejected, kicking any other electoral reform into the long grass at the same time. The 2015 Conservative government started to address the problem, but the process was left incomplete when PM Cameron resigned. The current government has bigger problems to address than electoral reform, so the constituency boundaries will soon be unchanged for 20 years.
    – alephzero
    Commented Jun 11, 2017 at 4:54

2 Answers 2


I live in Canada and both UK and Canada have what we call a ''first past the post voting system''. It means that, in order to win a seat, you just need to have the most vote in one specific area. I think you call them constituencies in the UK ? In Canada, it an electoral district.

1- problem number 1: You can win a seat with only 25% of support if the vote is really divided. It's rare to go that low, but possible.

Now imagine a situation where you have several seats. The conservatives get more support across the country but that does not mean they will win the election. They could, for example, lose a large number of seats with 49% of the votes. The labor party wining with only 51%. This 49% of votes is wasted since no one got elected.

Demonstration with only 3 seats L=labor C= conservative

  1. L=51% C=49%
  2. L=51% C=49%
  3. L=37% C=63%

The labor party is forming the new government with 2 seats despite having only 46% of the votes. It's a little extreme with just 3 sets but the principle stays the same with more seats unless you had a mechanism to be more representative of the vote.

2- problem number two: not all seats are equal. I do not know how bad is it in the UK but here, we have some electoral district that are protected to guaranty that a region will not loose it's political power. Normally, each electoral district represent a certain number of voters. The number is not the same for all districts since the demography is always changing. Most district are modified to fit this demographic criteria. However, cities always end up unrepresented, even if the regions do not have a specific protection.Protected district can have 3 or 4 times less people in it than the most populous district. Yet each of them elect only 1 person.

This mean that if a party is popular in the regions but not in the cities, he can win the majority of seats with a minority of votes.

In conclusion: this system is not good to represent the overall population but it's useful to create stable governments. Third parties can rarely elect more than 2 or 3 people even with 10% of the votes and the winner often wins with less than 50% of the votes.


It's an inherent characteristic of combining democracy via representatives with first-past-the-post voting.

Suppose you had a pie and you divided it into four pieces. Depending on the demographic distribution of the voters inside the pie; a party could win in non-proportional winner-takes-all system regardless of the plurality. The same principle drives gerrymandering.

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The illustration is of course exaggerated as legislatures have hundreds of seats.

  • I'd suggest something like my neighbours have: Mixed Member Proportional. I'm rather envious of them. Commented Oct 21, 2014 at 6:45
  • Proportional representation has been suggested a few times in the UK; problem is it tends not to benefit the government of the time.
    – Phil Lello
    Commented Mar 30, 2016 at 20:26

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