SNP MEP Alyn Smith said Tuesday that Brussels policymakers have already put to bed Tory and Labour claims that an independent Scotland would be kicked out of the EU.
Smith, standing for a third term in May's European Parliament election, made the assertion after delivering a keynote speech in Brussels to top bloc and Embassy officials at the request of the influential French think tank, Institut français des relations internationales.
"Not one of the experts here today had even the slightest doubt about Scotland's EU status on voting for independence," said Smith after his address alongside Catalan and Flemish counterparts in a public debate.
"One after another, they now seem to have reached the settled and commonsense view that Scotland is a case apart but that they want to draw the line there.
"My Belgian colleague on the panel said it perfectly - it is now politically untenable for any EU member to argue with a majority come September, even Spain, which is the real concern for EU Economic Commissionner Olli Rehn and his top aides here today."
The event's French hosts - with strong links to Paris government - said a consistent pattern of rising support for a Yes vote, bringing campaigners within a few swing percentage points of the target, had focused minds in Brussels and within key EU governments.
Read Alyn's speech in English.
Read Alyn's speech in French.