A prominent SNP MP has warned that backing a so-called People’s Vote on Brexit could present “all sorts of risks to a future independence referendum for nothing”.
Pete Wishart said the move could make it more difficult to resist calls for a similar confirmatory ballot in Scotland if nationalists were to win another indyref.
Nicola Sturgeon has said her party’s MPs would “undoubtedly” back a public vote on the final deal for leaving the EU if given the option.
The SNP leader and First Minister has also indicated she would seek a guarantee or “double lock” for such a ballot, for example requiring the support of all four UK nations before Britain could leave the EU.
SNP Westminster leader Ian Blackford has also suggested a guarantee that Scotland could hold another vote on independence.
However it is unclear if the SNP would withdraw its support for a People’s Vote if its demands for special conditions were not met.
Writing in The National, Mr Wishart said: “To say that we will sign up to a referendum without any guarantee that our Scottish national voice will be at least acknowledged is little more than an open invitation to have our national view ignored and disrespected all over again.
“By enthusiastically buying into this confirmatory vote for an EU referendum, we weaken our hand in resisting Unionist calls for a second vote on a successful indyref.
“And if they were successful in using this precedent against us, unreconciled Unionists would be working non-stop from the day after the referendum to ensure that a successful outcome would be overturned.
“Every apparatus of state would be deployed and they would ensure that the worst possible “deal” would be offered to the Scottish people in the hope that their Union could be rescued.”
Mr Wishart, the longest-serving MP in the SNP’s 35-strong Westminster group, said he considered it “very unlikely” a People’s Vote would come to fruition.
“We could be presenting all sorts of risks to a future independence referendum for nothing,” he added.
An SNP spokesman said: “We have made it clear that we would push strongly for any second EU referendum to have safeguards to ensure Scotland’s voice is protected in the event of Scotland voting remain again while the UK as a whole voted to leave.
“Scotland’s overwhelming vote to remain in 2016 – by far the most decisive vote of any of the UK nations – has been completely ignored, which underlines how Westminster completely fails to represent or protect Scotland’s vital national interests.”
Labour MP and People’s Vote supporter Ian Murray said: “We are inching towards a parliamentary majority for a People’s Vote, so this raises questions about how Pete Wishart and other SNP MPs will vote in the Commons.”
Scottish Liberal Democrat MSP Tavish Scott said: “The First Minister said SNP support for a People’s Vote was “unequivocal”.
“Her colleagues ought to be backing the campaign, not throwing up more roadblocks.”