Election Post #11: How have the national opinion polls changed since 2015?

June 7, 2017

In the days running up to the 2015 general election, the opinion polls suggested that the race was too close to call with the two major parties tied. All of the parties were prepared for a hung parliament, probably with Labour as the largest single party, and the final weeks of the campaign were dominated by questions about who would together in a coalition. With hindsight, this seemed to hurt Ed Miliband more than David Cameron as voters in marginal seats genuinely feared a Labour led government supported by the Scottish Nationalist Party. Despite this, the polls refused to shift and of the last the last ten taken before the election, five showed Labour and the Conservatives tied, two showed Labour ahead and three showed the Conservatives ahead. As the polls closed and the BBC released their exit poll, the nation was shocked when the Conservatives were projected to be only 10 seats short of an overall majority and 77 seats ahead of Labour. In the event, the Conservatives stormed to a small overall majority and outperformed their poll rating by around 4 percent and Labour underperformed theirs by roughly the same amount. An enquiry followed and everything from ‘shy Tories’ to unrepresentative samples was used to explain the polling-miss. 

The 2017 election could not be more different if it tried. Since 2015, there have been 250 GB/ UK-wide polls*. The Conservatives have led 245 of them, Labour 3 and two have been tied. In the poll of polls, the Conservatives have had a lead over Labour for the duration of the parliament with it ballooning out as support for UKIP declined following the EU referendum. Immediately following the general election, the parties remained roughly static in terms of support. The Conservatives tended to score in the high 30s and Labour in the low 30s, with UKIP third at just over 12 percent, the Liberal Democrats on 8 and the Greens scoring around 4. This remained the case for the rest of 2015 with UKIP’s support occasionally edging up and support for the Conservatives and Labour dropping as a consequence. Towards the end of February 2016, the Conservative share began to decline to the mid-thirties and Labour’s rose to a similar level. Between 17th March and 26th April, three individual polls showed Labour fractionally ahead. During this period, UKIP increased their standing to around 15 percent. At the 2016 local elections, Labour outperformed expectations but still lost 18 councillors in a set of elections that the party should have made gains in during its 6th year of opposition. Many of Jeremy Corbyn’s supporters were emboldened by the result, drawing attention to the BBC’s Projected National Share which had Labour ahead of the Conservatives on 31 percent to their 30. The Liberal Democrats had a good night, gaining 45 councillors and overall control of Watford Borough Council. 

After the Britain’s vote to leave the European Union on 23rd June 2016, the Conservatives and Labour remained in the low to mid-30s whilst UKIP topped out at an average of 17 percent. This was followed by a relatively fast decline back to the low teens and a rise in support for the Conservatives. After Theresa May replaced David Cameron as Prime Minister on 13th July 2016, the Conservatives rose into the low 40s with an Ipsos Mori poll putting the party on 45 percent. As Labour went through its second leadership contest in two years, its poll rating slumped to the high 20s but rose slightly towards the end of November. The average Conservative lead over Labour remained at 10 percent for the final few months of 2016 and beginning of 2017. Support for the Liberal Democrats rose to 10 percent, above its 2015 share of the vote but well below the levels that it achieved during the 2005-2010 parliament. 

Labour’s decline into the mid-20s recommenced in February 2017. Polls were routinely putting the party on 23-25 percent and the Conservatives clocked some eye watering 20 point leads over the official opposition. Comparisons have been drawn between Jeremy Corbyn and Michael Foot, who led Labour to a cataclysmic defeat in 1983 and endured similar poll numbers. UKIP and the Liberal Democrats began to jostle for third place on around 10 percent each and the Greens remained at a static level of roughly 3 percent. On 23rd February, Labour suffered an unprecedented defeat at the Copeland by-election. For the first time since 1960 without a defecting incumbent, the governing party gained the seat from the official opposition. Professor John Curtice commented that the defeat pointed to the polls being roughly correct about the state of the two major parties. In the weekend before Mrs May called the general election, a YouGov poll put the Conservatives on 44 percent, 21 points ahead of Labour, who polled 23 percent. Many pundits surmised that Labour were on course for a historic defeat, possibly its worst since 1935. 

Despite this, Labour’s fortunes began to change almost immediately with its poll rating rising from the mid-20s to low 30s. By early May, the party’s average poll rating was roughly equal with its 2015 share of the vote. The Conservatives immediately saw their share fly up into the high 40s with one pollster, ComRes, putting the party on the magic 50 percent. Most of this support seems to have come at the expense of UKIP with the local elections on 4th May confirming this as UKIP collapsed and lost over 130 councillors. On the same night, Labour did not just lose councillors but shedded them. The BBC’s Projected National Share had the Conservatives on 38 percent, 11 points ahead of Labour. The Conservative share was considerably lower than the opinion polls at the time suggested with Labour’s showing being about in-line with what was expected. Towards the end of May, Labour’s rating continued to improve with a succession of polls putting them above 35 percent but still well behind the Tories. 

In the final two weeks of the campaign, Labour’s support hit 39 percent in a YouGov poll, suggesting that gap between Conservative and Labour had been almost wiped out and was down to 4 points. On the same day, an Opinium poll put the Conservative lead at 6 points. Between them, the Conservatives and Labour are averaging around 80 percent and if this were to come true, it would be the largest combined share for the two major parties since 1979. The Liberal Democrats have stagnated at 8 percent, no better than their 2015 showing and UKIP have sunk to just over 4 percent. All of this suggests a return to a two-party system (at least in terms of votes) and in a big way. The final weekend of polls saw the major pollsters dividing on the size of the Conservative lead with five polls showing it varying from 1 to 12 points. The deciding factor seems to be the turnout of young people with pollsters that project a higher youth turnout showing a smaller lead for the Conservatives. Many pundits, therefore, have questioned whether these voters, who historically have low turnout, will bother to vote. If they don’t, it seems likely that the Conservatives will win a solid overall majority and about 45 percent of the vote with a lead of around 12 points over Labour. Labour are currently sitting on a post-2015 high at around 37 percent, and whilst it looks unlikely that they will get a share of the vote this high, they look almost certain to achieve an increased share compared to 2015 and could come within spitting distance of their 2005 winning share. 

There have been 14 polls from Scotland since 2015 and all of them have had the Scottish National Party comfortably in the lead. Since late 2015, the Conservatives have risen into second place ahead of Labour and at the 2016 Holyrood election, became the official opposition to the SNP who lost their overall majority. At the beginning of the campaign, the SNP saw their rating drop around 8 points compared to 2015 whilst the Conservatives surged to 30 percent and Labour slumped to a low of 15 percent. On these figures, the Conservatives looked set to increase their representation north of the border to around 12 seats, a post 1992 record whilst Labour’s sole seat, Edinburgh South, looked at risk. In line with national polling, Labour have seen some improvement in their poll rating in the last few weeks of the campaign with an Ipsos Mori putting them level with the Conservatives on 25 percent. Looking at the average of the last six Scottish polls, the Conservatives still look set to take around 8 seats in Scotland, the most since 1992. Whilst the SNP will still dominate the landscape, their share of the vote will be considerably down on the historic 50 percent that they achieved in 2015. The Liberal Democrats have not scored any higher than in 2015 in any of the last six Scotland-wide polls and whilst they may hold Orkney and Shetland, it looks unlikely that they will take any more seats apart from Jo Swinson having an outside chance in East Dunbartonshire. 

Despite taking a sensational lead in two of YouGov’s Welsh Barometer polls during the first few weeks of the campaign, the Conservatives have once again fallen behind Labour in Wales with both parties being up on their 2015 share. Labour could potentially take the most marginal seat in the United Kingdom, Gower, from the Conservatives as the polls suggest a small swing to Welsh Labour despite the rise of the Conservatives. Plaid Cyrmu, the Greens, UKIP and the Liberal Democrats are all currently polling lower than their 2015 share of the Welsh vote.

In 2015, David Cameron held a consistent lead over Ed Miliband in approval rating and Theresa May holds a similar lead over Jeremy Corbyn. In YouGov’s ‘best prime minister’ poll, Mrs May’s lead has shrunk over recent weeks with Jeremy Corbyn’s rating improving substantially. In the week following the Manchester attack, Theresa May moved into negative approval for the first time since becoming Prime Minister, marking the end of her extended honeymoon. The Conservative campaign has become considerably less presidential as Mrs May’s ratings have dropped but she is still seen as the best person to negotiate Brexit and manage Britain’s security despite Mr Corbyn’s leads on the NHS and education. 

Overall, the Conservatives still look set for victory tomorrow but how big a lead they manage to achieve over Labour is uncertain. The Liberal Democrats also look set to lose seats and equal their 2015 share, possibly marking the end of the party whilst UKIP’s support appears to be in freefall. When the exit poll is released at 10:00 tomorrow night, we will know which pollsters got it right and how big an impact the turnout of young people will have had on the election. If YouGov’s model, which currently suggests that no party will win an overall majority, turns out to be correct; serious questions will be asked about the future of polling. Although Labour are in a poor position in terms of trailing behind the Conservatives in voting intention and leadership rating, their recent improvement in the polls makes things seem just that little bit more uncertain. 

There are several polls due out this evening, we will update this post as they are released.

*250 polls as of lunchtime on 7th June 2015.

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