A UKIP victory in the 2014 European elections could prove a game-changer in shaking up Scotland's independence referendum, putting the Yes camp back in the race, leading academic expert Charlie Jeffrey told the IPPR at the launch of a new report on Englishness earlier this week.
Many Scots say that if Britain seemed likely to leave the EU, they could change their minds about independence. Polling suggests this could erode the current steady lead for the pro-Union campaign and turn the referendum into a neck-and-neck race.
Jeffrey said that a UKIP victory in the 2014 elections, and increasing pressure for an in/out referendum in the political and media reactions to this, would create a sense that Britain's membership is in doubt, just a few months before the independence vote next September.
Professor Jeffrey, who heads the University of Edinburgh's politics department, is one of the co-authors of the new IPPR report England and its two Unions, which shows that there are increasingly divergent views of the EU north and south of the border, with English voters becoming more strongly eurosceptic and taking the prospect of exit very seriously, while most Scots believe that the benefits of EU membership outweigh the disadvantages.
The Future of England survey 2012 showed English voters saying they would vote to leave the EU by 50% to 33% in a referendum on the UK's membership. By contrast, a February 2013 poll showed Scots would vote to stay in the EU by 53% to 34% in a referendum on UK membership, while EU membership in the event of an independent Scotland was supported by 61% to 33%.
The IPPR report notes that many Scottish voters say that the prospect of the UK leaving the EU could shift their vote in a 2014 independence referendum. A May 2013 panelbase survey found attitudes to independence tied 44% both for and against "if the UK was looking likely to withdraw from the EU", compared to an otherwise steady lead for the pro-Union campaign.
Most polls find almost a third of voters favouring independence and a majority against. "Euroscepticism elsewhere in the UK could potentially narrow that gap if the Scots feel they could be dragged out of the EU against their will ... English Euroscepticism may be as much of a challenge for the UK's union as is Alex Salmond", says the report.
British eurosceptic politicians in both UKIP and the Conservative Party have tended to be strongly pro-Union. Nigel Farage has been emphasising his ambitions to expand in Wales, Scotland and Northern Ireland. He told the Belfast Telegraph this week that he hoped to create a Dublin branch too.
The IPPR report shows that this Unionist perspective is not shared by the most anti-European voters. A strong sense of British identity is associated with more pro-EU attitudes, while the strength of English identity is strongly linked to Eurosceptic views. Those who say they are 'English not British' would vote to leave the EU by an overwhelming 72% to 17%, and those who are 'more English than British' by 58% to 28%. Those who are more British than English would vote to stay in by 45% to 37%
While UKIP want to end one Union and save another, there are English majorities for the Union with Scotland and, currently, for leaving the EU too, but that ticket is unpopular in Scotland.
Uncertainty over the EU had previously been difficult territory for Alex Salmond, as a claim to hold legal advice saying that an independent Scotland would not have to reapply for the EU unravelled. Increasing uncertainty about UK membership of the EU makes that a less potent charge, and could put the boot on the other foot. The issue also presents a potential "two unions" dilemma for pro-European Scots who support Alistair Darling and the 'Better Together' campaign.
There are currently Scottish majorities for staying in the UK and staying in the EU too. But this is not in Scottish hands. Only if the rise of English euroscepticism is checked would Scots be able to choose both unions for themselves.