Sabine Weyand, the brains behind the withdrawal agreement who deputises for Michel Barnier, told an audience in Berlin that an orderly withdrawal was the best Britain could hope for.
“I see no majority for a referendum in the House of Commons,” she confirmed after the event.
Ms Weyand reportedly accused some Remainers of “Cakeism" – a popular expression in Brussels referring to magical thinking whose usage was triggered by Boris Johnson claiming Britain could "have its cake and eat it" after Brexit.
She however clarified that she was not talking about the level of support in the country for another vote, but instead the mathematics in the Commons and political leadership for one.
The intervention, at a security conference, comes days after European Council president Donald Tusk said there was “no political force and no effective leadership” for another vote with the two main opposition parties committed to respecting the result of the 2016 referendum.
“I have always been with you, with all my heart,” he said, but added: “The facts are unmistakable”.
Mr Tusk as well as European Parliament Brexit coordinator have called on Theresa May to try and reach a cross party consensus to get backing for her deal – welcoming a Labour plan for changes to future relationship.
Speaking in Berlin Ms Weyand said the current political declaration was vague because the UK had not yet decided what kind of future relationship it wanted from with the bloc.
She added that Jeremy Corbyn's offer to Theresa May had triggered and interesting debate and this his proposals deserve to be discussed – the first public statement by the European Commission branch of the EU in the opposition’s proposals.
Despite the pessimism emanating from Brussels over the issue, Labour has however said it would support another public vote if the prime minister refuses to accept their demands for a customs union and close alignment with the single market.
The prime minister’s hands are somewhat tied in how far she can go to embrace Labour’s offer because a softer Brexit is likely to get an extremely hostile reception from her own party. Former party chair Grant Shapps, a critic of the prime minister from the party’s liberal wing, said on Monday that there was “no point winning Labour MPs, by losing Tories”.
But a second referendum would still not be certain with support from the Labour leadership – as a number of Labour MPs have said they would not vote for one in any circumstances, and only around a dozen Tory MPs have said they would support one.