The UK would be welcome to stay in the EU if it changed its mind about Brexit, Donald Tusk has suggested.
The European Council President told MEPs that the UK would leave the bloc unless it had a “change of heart”.
“We haven’t had a change of heart. Our hearts are still open for you.”
The comments were welcomed by Labour and Lib Dem MPs who want a referendum on the final Brexit deal but Leave Means Leave said the EU had to “accept the UK is a democracy”.
The government has said there will be no second vote ahead of the UK’s exit in March 2019.
Labour leader Jeremy Corbyn has also dismissed the idea while insisting that MPs have a “meaningful vote” in Parliament on the terms of the withdrawal agreement.
Former UKIP leader Nigel Farage floated the idea of a second vote last week, saying he was confident it would return a larger margin for Leave than in 2016 and it may be needed to settle the issue for a generation.
As it stands, the UK is due to leave the EU in March 2019.
The two sides reached a deal on so-called “divorce issues”, including money and citizens’ rights, in December and talks are now moving onto transitional arrangements and future co-operation.
Revised draft EU guidelines obtained by several UK newspapers suggest the EU is toughening its stance on what changes the UK can make on immigration, trade and fishing during a roughly two year transition period.
Speaking in the European Parliament in Strasbourg, Mr Tusk said he believed the other 27 EU members would maintain their unity when the talks resumed in March.
“The hardest work is still ahead of us, and time is limited,” he said.
“If the UK government sticks to its decision to leave, Brexit will become a reality – with all its negative consequences – in March next year. Unless there is a change of heart among our British friends.
“Wasn’t it David Davis himself who said ‘if a democracy cannot change its mind, it ceases to be a democracy’.
“We, here on the continent, haven’t had a change of heart. Our hearts are still open to you.”
Labour MP Daniel Zeichner, a supporter of the Best for Britain group, which was launched last year by pro-EU campaigner Gina Miller, said the option to remain in the EU must be kept open.
“The world has moved on since the summer of 2016, and in a time of great political division and tension across the world, it seems ever more foolish to stray from our European neighbours,” he said.
“We are stronger together, and it becomes increasingly clear that the current path is extremely damaging.”
But Leave Means Leave, which grew out of the Vote Leave campaign during the 2016 referendum, said Brussels had a history of not listening to the views of voters.
“Donald Tusk and Jean-Claude Juncker need to accept that Britain is a democracy – something the EU knows very little about,” said its co-chair Richard Tice.
“The British people voted to leave the EU and this decision will not be reversed, despite their best efforts.”
And Tory MEP Syed Kamall said EU officials should be focusing on getting the best outcome for their citizens rather than indulging in political posturing over Brexit.
“Voters, citizens and workers don’t care about legal technicalities, they don’t sit at home hoping the UK is made an example of. They simply want both sides to sort it out,” he said.