THE Remain campaign's lead in Scotland "may not be secure" and could evaporate during the final stages of the EU referendum battle, according to new research.

Focus groups conducted with Scots voters showed support for the EU, even among those planning to back Remain in the June 23 poll, is weak.

A large proportion of voters are planning to support the UK staying in the EU not because they are convinced about the benefits of membership, but because they are unsure about the impact of leaving, researchers from think-tank IPPR Scotland and polling company Ipsos MORI discovered.

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They also found that Scots view the EU referendum as less important than the vote on independence 20 months ago.

Despite Nicola Sturgeon's warning that a second independence referendum would "almost certainly" follow a Brexit vote that was not supported in Scotland, most people are not making up their minds based on the prospects for a re-run of the 2014 referendum.

The view was also reflected in the latest bookies' odds.

Ladbrokes quoted odds of 9/4 that Scotland votes to Remain but the UK as a whole votes to Leave.

The bookmaker said, on that basis, it was a 5/1 shot that a second independence referendum would take place before 2020.

A poll by TNS earlier this week suggested 44 per cent of Scots would back independence if a post-Brexit referendum was called, lower than the 45 per cent who voted Yes in 2014.

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David Cameron again warned that Brexit could prompt a second independence referendum as he made the case for staying in the EU during Prime Minister's Questions.

The independent, centre-left think tank IPPR Scotland and pollsters Ipsos MORI conducted detailed interviews with voters across a range of age groups in Edinburgh, Elgin and Perth between May 9 and 11.

In all, 25 people representative of the electorate, were interviewed in an effort to understand the factors shaping public opinion.

One voter in Elgin summed up his support for Remain as sticking with "the devil you know".

The researchers concluded: "While the research suggests that the Remain lead looks strong, it may not be secure and it may change over the short campaign, depending on the nature of the arguments presented."

In a worrying conclusion for the Remain campaign, they found the Leave side's arguments - particularly about taking back control from Brussels - were cutting through more strongly with the public.

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They said there was "no clear strong European identity among Scots" after hearing the EU described as remote and undemocratic.

When they were asked to outline the pros and cons of EU memberships, most people in the focus groups found it "easier to be critical and express those criticisms with feeling and passion".

Most accused both sides of scaremongering, the research also found, and wanted more information they could trust.

Voters also felt the referendum lacked a "specifically Scottish dimension" as many of the issues at stake - such as security and immigration - are reserved to Westminster.

Some believed Scottish politicians were using the EU referendum to gain a mandate for a second independence vote, despite the SNP's staunch support for a Remain vote.

However, most said their vote would not be influenced by what the outcome might mean for a future independence referendum.

Russell Gunson, Director of IPPR Scotland, said: "It seems the EU referendum will be more of a ‘tinman’ referendum in Scotland, lacking heart and lacking passion, especially compared to the independence referendum.

"While the polls may show support for Remain in Scotland, our research shows this support is potentially quite soft, and may not be sufficient to translate into high turnout on the day."

Mark Diffley, Director at Ipsos MORI Scotland said: "Voters in Scotland are going to the polls in two weeks, facing the fourth significant political decision in under two years.

"It is clear from this research that, despite the importance of this referendum, Scots feel less passionate and engaged than with previous votes, especially the 2014 independence referendum."