Nicola Sturgeon has announced a broad timetable for a second Scottish independence referendum by 2021 if Scotland is taken out of the European Union.
In the 2014 referendum, the No campaign won by 55 per cent to 45. In the five years since that vote Scotland has had two general elections, a Scottish Parliament vote, the Brexit referendum, a change of First Minister and a change of Prime Minister.
In light of all this political upheaval, Ferret Fact Service looked at 100 polls involving around 100,000 people since the vote in September 2014, to see whether the Scottish electorate’s views have changed on the independence question.
Before the 2014 referendum
The official campaign period began on 30 May, 16 weeks before votes were cast. The first poll to be released after this date, by IPSOS-Mori, found 34 per cent in favour of independence, with 54 per cent against and 13 per cent undecided.
Compared to the result of the referendum, this shows an 11-point increase in support for independence during the campaign period. The No campaign gained one point, indicating the majority of initially undecided voters were persuaded by the Yes campaign.
Scottish independence polling since the referendum
The first poll after the vote, conducted in October 2014 showed 49 per cent support for Yes and only 45 per cent for No. Since then 11 polls have shown a lead for Scottish independence.
The most recent of these was in March 2017 by IPSOS-Mori which showed 47 per cent in favour with 46 per cent opposed, counting those who were almost certain to vote. The highest lead for independence was nine points in August 2015.
All the other polls since the referendum have shown a lead for No, until Lord Ashcroft’s landmark survey in August 2019. The highest lead for a No vote was 20 points in May 2019, however this poll had a different question format to usual, asking respondents whether they would like to Leave or Remain in the UK. The 20-point lead was matched using a standard question in June 2017.
Yes took the lead for the first time since March 2017, with a two-point margin in the first poll taken since Boris Johnson took office at Westminster.
What affected people’s answers?
While the majority of polls have remained broadly in favour of staying in the United Kingdom, some political events appear to have shifted public opinion, although there is little evidence that they have had lasting impact overall.
After the 2014 referendum there was a significant boost in polling support for a Yes vote. Four of the first six surveys taken after the result between October 2014 and February 2015 showed independence in the lead, with one returning a tie and one in favour of No.
Another indicated increase in support for a Yes vote took place after the Brexit referendum and ensuing resignation of David Cameron. Three polls in the following week showed support for Yes in the ascendancy.
The most recent poll, taken after Nicola Sturgeon’s announcement that she would seek another referendum, was the closest since March 2017.
The highest consistent period for support of a No vote was around the 2017 general election, when five polls showed at least a 10-point lead for staying in the UK.
The first poll with Yes in lead since 2017 took place after Boris Johnson won the Tory leadership contest and became Prime Minister.
Different questions, different answers
The polling on Scottish independence has been commissioned by different groups including newspapers, blogs and pressure groups, and conducted by nine separate polling companies.
This means that the question of whether Scotland should be independent has been asked in a few different ways. Polls commissioned by pro-union organisation Scotland in Union were likely to show a significant majority against independence, but the question asked was ‘Should Scotland remain in the UK or leave the UK?’ with a choice between ‘Remain’ or ‘Leave’.
The most common question asked was ‘Should Scotland be an independent country?’, which mirrored the referendum question.
However, a number of slightly altered wordings were also used, including “Knowing what you know now, if the independence referendum was tomorrow how would you vote?” and “If there were a fresh referendum on Scottish independence tomorrow, then how would you vote?”. These may also affect the way a person answers.
Much was made before the vote in 2014 of the impact of the question’s wording. Originally, the Scottish Government proposed the question, “Do you agree that Scotland should be an independent country?”, but the Electoral Commission tweaked the wording to a simpler, “Should Scotland be an independent country?”.
They found that the original wording was “not neutral because the phrase ‘Do you agree …?’ could lead people towards voting Yes”.
This fact check was updated on 29 August 2019 to include new opinion polls.
Ferret Fact Service (FFS) is a non-partisan fact checker, working to the International Fact-Checking Network fact-checkers’ code of principles. All the sources used in our checks are publicly available and the FFS fact-checking methodology can be viewed here. Want to suggest a fact check? Email us at firstname.lastname@example.org or join our Facebook group.