Predicting the UK 2017 General Election

James Sherwin-Smith
5 min readApr 19, 2017


I’m no Nate Silver, nor do I aspire to be, an albeit fictional, Joey Lucas type. I don’t have access to banks of private polling data. I’m an intrigued amateur who predicted the 2015 result (a Conservative majority) with a 1% (3 seats) margin of error, while most of the professionals got it badly wrong. So I thought I’d chance my arm again.

My prediction

Overall I predict the following result for the General Election 2017:

  • Conservatives 338 (+8 seats)
  • Labour 210 (-19 seats)
  • Liberal Democrats 44 (+35 seats)
  • SNP 31 (-23 seats)
  • Others 27 (-1 seats)

This would give the government a small increase in their majority from 17 to 33. The big winners should be the Liberal Democrats, with the SNP and Labour losing c. 20 seats each overall.


An unexpected ‘snap’ General Election was called yesterday by the UK Prime Minister, Theresa May, less than two years since the last election in May 2015. A few things have changed since then, however:

  • EU referendum. The UK held a referendum in June 2016 on whether to leave the EU. This was a promise made by the last Prime Minister, David Cameron, as part of his 2015 election manifesto. The country chose to ‘Brexit’ by a narrow margin of 52:48 on a turnout of 72%.
  • Main party leadership changes. After significant losses in the General Election, both Ed Miliband and Nick Clegg stepped down as leaders of the Labour and Liberal Democrat parties, and were replaced by Jeremy Corbyn and Tim Farron respectively. After the referendum result, David Cameron resigned, and Theresa May became Prime Minister.
  • UKIP. Following a Brexit vote, Nigel Farage stepped down as leader of the UK Independence Party, and was replaced by Paul Nuttall. Given UKIP’s primary goal of the UK leaving the EU is now in progress following the triggering of Article 50 by Theresa May, it is unlikely that UKIP will be able to repeat its 2015 result when it received 13% of the vote (but only a single seat).
  • SNP. The Scottish National Party won an unprecedented 56 of 59 seats in the 2015 General Election. This election followed the 2014 referendum on Scottish independence with the electorate voting 55:45 against ceding from the United Kingdom. The strong support for the SNP in 2015, and the fact that Scotland voted 62:38 to remain in the EU in 2016, has led calls to another referendum on independence by the SNP leader, Nicola Sturgeon.

My hypotheses

  1. There will be a significant swing from UKIP to the Conservatives (i.e. the Brexit vote).
    Theresa May has signalled taking a strong line in the negotiations with the EU over the terms of the UK’s departure, with rhetoric favouring a so-called ‘hard’ Brexit such as “no deal for Britain is better than a bad deal”. The primary reason for calling this election was to secure a strong mandate for those negotiations, as well as push out the timing of the next General Election to 2022 and restrict the impact of the next election on Brexit negotiations (and vice versa). For most UKIP voters, the process of leaving the EU has now begun, and it could be argued that the best chance of making it a success will be an empowered Theresa May. Analysis by YouGov suggests 66% of UKIP voters have previously voted Conservative, but only 24% for Labour. Since replacing the well known Farage, the relatively unknown Nuttall has had little time to establish himself with the UKIP faithful.
    [The Copeland by-election result from earlier this year is a useful case study. After normalising for low turnout (election fatigue is almost certainly going to be a factor in June), the UKIP vote fell by 57%, with the Conservatives the main beneficiaries, winning the seat from Labour for the first time in 34 years.]
  2. There will be a modest swing from the Conservatives, and a lesser degree from Labour, towards the Liberal Democrats (i.e. the Remain vote).
    The Liberal Democrats were demolished in 2015 following their coalition with the Conservatives in 2010, with the party losing 15% of the vote and 49 seats. With the Liberal Democrats positioning themselves as the pro-EU party, they could pick up disaffected voters who either voted to remain, or have had a change of heart since voting to leave in June last year. However, they face several challenges: their new leader is not well known, and many of the seats they lost in 2015 were in parts of the country that voted to leave the EU in 2016 e.g. the south-west.
    [The recent Richmond Park by-election result is a positive sign, albeit under unusual circumstances: the Liberal Democrats won back the seat they lost to Zac Goldsmith in 2010 with a large swing of 22% from the Conservatives. The Liberal Democrats ran a distinctly pro-EU campaign in an area of London that voted to remain with additional support from More United, whereas Goldsmith, who had earlier that year lost the London Mayoral election, ran as an independent given the Conservative party stance on Heathrow.]
  3. There will be a small swing away from the SNP towards Labour and the Liberal Democrats (i.e. the pro Union vote).
    The Scottish electoral map changed substantially in 2015, with the SNP gaining 50 seats, Labour losing 40, and the Liberal Democrats losing 10. With Sturgeon pushing for IndyRef2 following the UK decision to leave the EU, there will be a group of voters who gave the SNP their support following a No vote to leave the Union, but who want to stay in the UK, and will so vote along more traditional party lines. [The Conservatives held their single seat in Scotland in 2015, and therefore have little to lose but are also unlikely to make any gains.]

My calculations

  1. Impact of a UKIP collapse: Con +32, Lab -30, LD -1, UKIP -1.
    This is based on these constituencies changing hards in decreasing likelihood: Chester, Halifax, Clacton, Newcastle-Under-Lyme, Ilford, North Brentford & Isleworth, Wirral West, Barrow & Furness, Wolverhampton South West, Dewsbury, Walsall North, Derbyshire North East, Enfield North, Stoke-On-Trent South, Lancaster & Fleetwood, Bridgend, Middlesbrough South & Cleveland East, Wakefield, Birmingham Northfield, Wrexham, Eltham, [Copeland based on 2015 results], Gedling, Clwyd South, Mansfield, Dudley North, Alyn & Deeside, Blackpool South, Delyn, Hyndburn, Norfolk North, Scunthorpe, Bishop Auckland.
  2. Impact of a pro-EU vote: LD +31, Con -24, Lab -7.
    This is based on these constituencies changing hards in decreasing likelihood: Cambridge, Eastbourne, Lewes, Thornbury & Yate, Twickenham, Kingston & Surbiton, St Ives, Torbay, Bath, Burnley, Sutton & Cheam, Bermondsey & Old Southwark, Yeovil, Colchester, Portsmouth South, Berwick-Upon-Tweed, Cheadle, Cardiff Central, Brecon & Radnorshire, Cheltenham, Devon North, Wells, Cornwall North, Hazel Grove, Bristol West, St Austell & Newquay, Birmingham Yardley, Eastleigh, Montgomeryshire, Oxford West & Abingdon, Bradford East.
  3. Impact of pro-Union vote in Scotland: SNP -23, Lab +18, LD +5.
    This is based on these constituencies changing hards in decreasing likelihood: Dunbartonshire East; Renfrewshire East, Edinburgh West; Edinburgh North & Leith; Paisley & Renfrewshire South; East Lothian; Fife North East; Rutherglen & Hamilton; Caithness, Sutherland & Easter Ross; West Paisley & Renfrewshire North; Aberdeen South; Kirkcaldy & Cowdenbeath; Edinburgh South West; Airdrie & Shotts; Dunfermline & Fife West; Glasgow Central; Lanark & Hamilton East; Ochil & Perthshire South; Ross, Skye & Lochaber; Edinburgh East; Coatbridge, Chryston & Bellshill; Midlothian; Linlithgow & Falkirk East.



James Sherwin-Smith

Engineer by education, Consultant by experience, Entrepreneur at heart. My professional focus is #fintech & #payments, I’m an #avgeek + #cricket fan