Predicting Past the Post

A voting division in the Commons Chamber. Source: Wikimedia Commons/UK Parliament

The UK uses the First-Past-The-Post voting system to elect 650 MPs to its 650 constituencies. FPTP is a local voting system rather than a national one. This means that, in effect, 650 local elections will take place across the UK on Thursday 12th December; whichever party wins the most local elections wins the general election overall – and, in all likelihood, a parliamentary majority in the House of Commons, the lower chamber – 326 seats are required in order to win this majority. The upper chamber, the House of Lords, is unelected, and is instead arbitrarily appointed.

Polling for FPTP elections is notoriously difficult as polling can only normally give a glimpse of the national picture. For example; according to polling aggregation taken from data collected during the week ending 1st December, the Conservatives are around 8% ahead of Labour, meaning that, on paper, the Conservatives can expect to win around 357 seats, up about 30 from their 2017 total, and Labour around 211, down around 51 from their 2017 tally. This figure is calculated by adding 8% to the Conservative vote in all of the 650 constituencies in which the party is standing. I will now explain and exemplify why this means that the expected seat tallies might be incorrect.


Current national polling has the Scottish National Party (SNP) on around 3% of the national vote. As this is such a minute national share, it would deliver them no seats whatsoever. However, the SNP, as their name suggests, only stands candidates in Scottish seats – 59 out of 650. Thus, their 3% vote share is highly concentrated to just a handful of seats. For example, in 2015, the SNP won 56 of Scotland’s 59 seats, becoming the UK’s third-largest party, on just 4.7% of the national vote. This time around, their roughly 3% of the national vote, which would likely be around 45% of the popular vote in Scotland, could see the party win somewhere between 45-50 seats.

This is a strong example of how geographical concentration in the FPTP system can mean that a party’s parliamentary representation can end up being wildly disproportionate to its vote share. 

Scotland’s First Minister Nicola Sturgeon – even though the SNP will only win a minute share of the national vote, she could end up playing a decisive role in the next parliament. Source: Wikimedia Commons/Scottish Government

Esher and Walton

Esher and Walton is an affluent, safe Conservative seat in the county of Surrey, just outside of London. It is represented by the current Foreign Secretary, and arch-Brexiteer, Dominic Raab, yet Esher and Walton voted comfortably to remain in the EU (58%) in 2016. In 2017, Raab was returned as the MP there with a huge majority of 23,298 votes, winning 58.6% of all votes cast in Esher and Walton. There, in 2017, the Liberal Democrats finished in a very distant 3rd place, with 17.3% of all votes cast.

In this election cycle, the Liberal Democrats are currently sitting at around 15% in the national polls, well under half of the Conservatives’ predicted vote share, yet they may well overturn Raab’s huge majority. What national polls often fail to detect in FPTP elections is the impact of strong local campaigning, such as that currently being undertaken by the Liberal Democrats in Esher and Walton, and of voter identities. Esher and Walton voted to remain, Raab did not. The Liberal Democrats’ candidate, Monica Harding, is campaigning on an unashamedly pro-EU platform. This style of campaigning by the Liberal Democrats appears to be having an impact in many wealthier Remain-voting areas, but is turning voters away in more Leave-leaning areas.

Thus, much like the SNP’s vote in Scotland, the Liberal Democrats will probably cause upsets as their vote share is likely to be concentrated in certain Remain-leaning areas on 12th December. Ergo, they could potentially win around 30 seats on a relatively small share of the national vote, whilst failing to cross the 5% ‘deposit threshold’ in other seats.


Hartlepool, a town on the coast of North-East England, is one of the poorest places in the UK. It has been a Labour stronghold for decades, but voted to leave the EU in 2016 by a huge margin of 69.6% to 30.4%. Labour’s Mike Hill, a Remainer, has a majority of 7,650. Whilst nowhere near as safe as Dominic Raab’s seat of Esher and Walton, it would still take a hefty swing away from Labour in order to unseat Hill.

Enter, the Brexit Party. Nigel Farage’s fledgling party swept the EU elections in May 2019, winning 29 of the UK’s 73 European seats, yet his party has since stalled, and is currently sitting between 4% and 6% in national polls.

In any account, the Brexit Party could not possibly win enough seats to form a majority government, as it is only contesting 275 seats.

However, Richard Tice, the Brexit Party’s candidate in Hartlepool, has become the party’s most recognisable face after Farage himself. This means that the Brexit Party is strongly biting into the Leave vote in Hartlepool. Thus, it is also eating into Labour’s core vote in the constituency. The Brexit Party is tanking in national polling, and may well fail to cross the ‘deposit threshold’ across the country on 12th December, but a concentrated vote may well see them take a handful of Labour-held, strongly Leave-voting seats like Hartlepool – a sort-of counterweight to the Liberal Democrats’ probable inroads in seats such as Esher and Walton.

Northern Ireland

Due to its unusual modern history, no major UK-wide party holds any of Northern Ireland’s 18 seats, nor do most stand candidates there by convention. Vote shares in Northern Ireland largely fall along sectarian lines. In 2017, almost all Protestant-majority areas returned a Democratic Unionist Party (DUP) MP, whilst all Catholic areas returned a Sinn Fein MP.

Most national polls do not question Northern Irish voters and do not take into account Northern Ireland-only parties. This is to the detriment of polling.

Following the 2017 election, the DUP ended up propping up a minority Conservative government. The success of the DUP in Northern Ireland, and their consequent role as kingmaker in parliament, went undetected by pollsters – and did not become clear until the morning after the 2017 election – as most pollsters ignore/avoid Northern Ireland.

I hope that this explanation, with these examples, demonstrates why a strong Conservative lead in national polling may yet prove to be meaningless. Having written this, though, I do believe that we will ultimately see a small Conservative majority in the House of Commons, similar to the one that the party won in the 2015 election.

A protester outside of the UK Parliament. Boris Johnson has become a divisive figure in this election campaign. Source: Wikimedia Commons

Luke Sandford

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