EU nationals living in Scotland could tip the balance towards independence if a second referendum was held before Brexit, it is claimed.

The timing of a vote could be crucial for a Yes win as migrants are likely to be disenfranchised after Brexit, according to a new paper from the Scottish Centre on European Relations.

First Minister Nicola Sturgeon announced in June that plans for a second referendum would be put on hold after previously calling for a vote before spring 2019.

EU citizens were allowed to vote in the 2014 referendum, in which 55% of people voted against Scotland becoming an independent country.

In their paper, authors Richard Marsh and Favian Zuleeg argue that voting rights would no longer be protected by EU treaties when the UK leaves the bloc.

"In effect, this would exclude a significant proportion of the current electorate from a potential future Scottish independence referendum, if the referendum takes place after Brexit," they said.

They estimate that by 2020 there could be around 215,000 EU nationals living in Scotland who would be old enough to vote.

They said: "If all EU citizens vote Yes to independence, it could have a significant impact.

"If the 2020 projected number of EU citizens were assumed to have unanimously moved from the No to the Yes cohort in the 2014 referendum, it would have been just enough to switch the result, resulting in a 51% Yes vote.

"While there can be no definite predictions, it seems clear that the decision when to exit the EU and when to hold an independence referendum could have a material impact on the outcome."

An SNP spokesman said it is "only right" that everyone in Scotland would be given the chance to vote in a second referendum.

"The SNP will work hard to convince everyone – no matter where they are from – of the benefits that independence could bring for everyone in Scotland," they added.