For example, a coalition of Conservatives and Labour, as currently this would command a clear majority and represent a greater majority of the population.

Surely representing more of the population is desirable and there is nothing to stop the major parties from being more closely aligned in their politics than with much smaller parties.

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    What would be the policy of such a grand coalition? The individual parties are already having trouble getting everyone in their own party on the same page. Surely putting them all in one party would make it even more difficult to find a consensus?
    – JJJ
    Commented Apr 9, 2019 at 12:35
  • And if Jo Citizen is dissatisfied with the performance of the (grand coalition) government, which party should they vote for to oust them in the following election? Commented Apr 9, 2019 at 19:31
  • @JJJ: Isn't that an issue that would occur in any coalition between parties that are, in other legislative periods, opposing one another? Commented Apr 9, 2019 at 23:08
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    You are asking that question, and your name is Theresa . . . .?
    – peterG
    Commented Apr 10, 2019 at 0:01

4 Answers 4


There is nothing in law to stop them, but ... why would they? Sure it would let them get things through parliament very easily, but what would they want to get through parliament. The two main parties in the UK disagree on the vast majority of policy areas - that's why they are different parties. If there was a clear shared agenda, they would likely form a party around that.

It's also worth noting, from a practical point of view forming a coalition with the party seen as your main rival would usually severely damage your credibility with your voters, and would likely make re-election difficult.

There are situations where this makes sense. In times of crisis, countries are sometimes led by a so-called "Government of National Unity" or "National Government" (see here and here for a more UK-centric point) but these are very rare as they require a crisis so great that the political differences between the two main parties are rendered irrelevant (in practical terms this usually means a war).

Another point worth making is that in one area of the UK, this is compulsory! The Northern Ireland executive requires power to be shared between the largest Republican party (which is usually also left wing) and the largest Unionist party (usually also right wing). The executive is led by the First Minister and deputy First Minister who have the same governmental power, resulting in a duumvirate. This was designed to ensure that both Republicans and Unionists felt represented in government. The downsides of such an arrangement are now being keenly felt, as the Sinn Féin and the DUP currently have seemingly irreconcilable differences which has caused the power sharing to collapse and has caused a crisis in Northern Ireland, since there currently is no executive and there cannot be one until the parties come to an agreement.

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    You make it seem like a grand coalition would be always and everywhere something extraordinary, but actually this is quite a common form of government in some countries. In Austria this has been the most common constellation since WW2, and in Germany three of the last four governments were grand coalitions. Commented Apr 9, 2019 at 17:37
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    yes, what leftaroundabout said. The reason for a big coalition is not that there's great turmoil or extraordinary situations. The reason is that a coalition between a big and a small party fails to reach a majority. As soon is it happens in the UK that a big party can't form a majority government with small closely aligned parties (yes possibly plural) you will have a coalition between the 2 major parties. They still have a fair bit of common ground to legislate :p
    – xyious
    Commented Apr 9, 2019 at 18:55
  • Neither of you are wrong, and it would be interesting to see this answer expanded to address your points and to address the topic more broadly. However, from a UK perspective, which this question commands, CoedRhyfelwr is right on the money as-is. Commented Apr 10, 2019 at 0:43
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    @leftaroundabout Isn't that a product of the voting system? The election to the UK's House of Commons is FPTP; Austria's equivalent election is proportional representation and Germany's is a hybrid. In contrast to PR, FPTP tends to generate two large parties that will necessarily be opposed (otherwise what is the point) along with some smaller ones. People who support FPTP tend to believe (rightly or wrongly) that PR produces ‘weak’ coalition governments instead of ‘strong’ majority governments.
    – Lag
    Commented Apr 10, 2019 at 11:53

Technically correct but politically almost inconceivable. This is usually referred to as a "government of national unity", and was present during the crisis from 1931-45.

Doing so without a clear national emergency would result in huge outrage from the party base and likely electoral ostracism at the next election.

Surely representing more of the population is desirable

Almost nobody cares about this in UK politics.


This is known as a grand coalition or specifically as has happened in the UK, National Government.

They tend to occur only at times of national crisis, such as wars. In normal times they are unlikely to occur as the ideological differences are too great to maintain unity.


If a store says that you have to pay 51 for something, are you going to ask "Is there any way I can pay 60?" A ruling coalition requires 51% of the vote. These votes are purchased by making concessions. The larger a party is, the more bargaining power they have for demanding concessions. So, no, it's not the case that "representing more of the population is desirable". Strategically, the optimum situation is to represent the bare minimum required to hold power, as that requires the least concessions. In a country like the US where there's a separately elected head of government with veto power, there's more incentive to work towards a veto-proof super-majority.

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    Bargaining power is not directly related to the number of MPs. A small party that can pact with any of the other parties without alienating its voters may have a greater bargaining power than a big party that only has a viable ally. Internal party dynamics also play a part; if a party leadership feels threatened if they do not get the support (for example an incumbent PM that will lose the position if there is no pact is likely to be replaced as head of the party) they will have less bargaining power. Politics (and life) is complicated.
    – SJuan76
    Commented Apr 9, 2019 at 15:28
  • 1
    "A ruling coalition requires 51% of the vote": it requires > 50% of MPs in parliament, which (given first-past-the-post) is unlikely to correlate with the same percentage of votes. Commented Apr 9, 2019 at 16:06
  • @SJuan76 That there are other factors doesn't contradict the fact that this is one factor. Commented Apr 9, 2019 at 16:41
  • @SteveMelnikoff I didn't say "popular vote". Commented Apr 9, 2019 at 16:41
  • True, but the wording was, at best, ambiguous. Commented Apr 9, 2019 at 17:16

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