UK Prime Minister Andy Burnham has announced plans for a national commission to reform the electoral system.
Projected seat totals by party changed substantially when the first-past-the-post system used in UK House of Commons elections was compared with calculations under systems designed to increase proportionality.
The key issue is not declaring one system better than another, but determining how closely the relationship between vote share and seat totals should be aligned.
3-Line Summary
1. Proportional representation reflects vote shares more closely in seat totals.
2. Labour was projected to receive 39% of the seats with 26% of the vote.
3. Discussing reform and changing the system are not yet the same thing.
How 26% of the Vote Becomes 39% of the Seats
The first-past-the-post system (FPTP) used in UK House of Commons elections selects one candidate who receives the most votes in each of 650 constituencies. Voters mark one vote next to the name of their preferred candidate, and the candidate who finishes first in that constituency becomes an MP. The system is considered easy to understand and conducive to producing single-party governments, but it is also criticized because national vote shares and seat shares can diverge significantly.
According to a report published by The Guardian on September 30, citing a recent opinion-poll-based model by More in Common, Labour was estimated to win 250 seats, or 39% of the seats, with 26% of the vote. Even so, this falls short of a majority. The structure means that a party can win more seats by finishing first in many constituencies, even without leading by a wide margin in vote share.
It is important that this estimate is a model based on a particular opinion poll, not an actual election result. Nevertheless, it clearly shows why “leading in the national vote” and “holding a majority of seats” do not necessarily move in proportion under a first-past-the-post system.
How Three Forms of Proportional Representation Calculate Seats Differently
The systems proposed for increasing proportionality are regional party-list representation, the single transferable vote (STV), and the additional member system (AMS). Regional party-list representation reflects party votes at the regional level in the allocation of seats. STV is designed so that voters rank candidates by preference and votes can be transferred.
AMS involves casting two votes: one for a constituency candidate and one for a party. Constituency MPs are elected using the first-past-the-post system, and additional members are allocated based on regional party votes to compensate across the total number of seats. The Scottish Parliament uses this system and consists of 73 constituency members and 56 additional members from 8 regions.
Under the same model, Labour’s share of seats was estimated at 26% under regional party-list representation, 26% under AMS, and 27% under STV. By contrast, the Greens hold 3 seats under the current first-past-the-post system but were projected to win more than 50 seats under all three proportional systems. The clearest point in this comparison is that the leading party’s seat bonus declines while the number of seats held by smaller parties that receive votes nationwide increases.
Why the Possibility of Coalition and Minority Governments Increases
Greater proportionality makes it more difficult for one party to win a majority and increases the likelihood of coalition or minority governments. The Guardian’s model found that no system would produce a single party with an outright majority. Combinations of Labour, the Liberal Democrats, the Greens, the Scottish National Party (SNP), and Plaid Cymru, or combinations of Reform, the Conservatives, and Restore Britain, could provide routes to forming a government, according to the calculations.
This means that seats would more closely resemble vote totals, but negotiations among parties after the election would become an important stage in forming a government. “How much of one vote is transferred into seats” and “who can form a government alone” are criteria that can be traded off against each other.
Reports that Prime Minister Burnham has announced plans for a national commission, supported by more than 100 Labour MPs as well as the Liberal Democrats, the Greens, the SNP, and Plaid Cymru, show that discussion of reform has grown. However, the systems in the model above are projections for comparison, not confirmed outcomes of a decision to introduce them. Ultimately, the debate over proportional representation in the UK remains a choice between how much weight to give the proportion of representation and how governments are formed.
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Tags #UKelections #proportionalrepresentation #UKHouseofCommons #firstpastthepost #FPTP #additionalmembersystem #AMS #singletransferablevote #STV #partylistrepresentation #electoralreform #Labour #UKpolitics