Donald Tusk issued a rallying call to the “increasing majority” of British people who want to cancel Brexit and stay in the EU, hours before MPs were given the chance to back a second referendum.

In a stirring intervention on Wednesday, the European council president praised those who marched on the streets of London and the millions who are petitioning the government to revoke article 50.

Speaking to the European parliament, Tusk reprimanded those who voiced concerns about a potential lengthy extension to article 50 in the event of the Commons rejecting the withdrawal agreement again this week.

Tusk said: “Let me make one personal remark to the members of this parliament. Before the European council, I said that we should be open to a long extension if the UK wishes to rethink its Brexit strategy, which would of course mean the UK’s participation in the European parliament elections. And then there were voices saying that this would be harmful or inconvenient to some of you.

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“Let me be clear: such thinking is unacceptable. You cannot betray the 6 million people who signed the petition to revoke article 50, the 1 million people who marched for a people’s vote, or the increasing majority of people who want to remain in the European Union.”

To heckling from Ukip MEPs, Tusk went on: “They may feel that they are not sufficiently represented by the UK parliament, but they must feel that they are represented by you in this chamber. Because they are Europeans.”

In London, MPs voted to seize control of the parliamentary timetable on Monday to allow the House of Commons to explore over the coming days whether there could be support for alternatives to Theresa May’s twice-defeated Brexit deal, including a possible second public vote.

That proposal, put forward by the former Labour cabinet minister Margaret Beckett, lost by 27 votes on Wednesday evening, the second smallest loss among the eight solutions to the Brexit impasse, offering some hope to campaigners in future votes to come. But EU sources said they were concerned that the UK parliament was still unable to coalesce around a solution, saying: “Our interlocutor remains the British government.”

The Guardian revealed on Wednesday morning that the EU has pencilled in April Fools’ Day 2020 as a first day for the UK outside the bloc since 1973 if May fails to ratify her deal but seeks a long extension of article 50 on the basis that a new plan has emerged.

The former Ukip leader Nigel Farage responded to Tusk by describing him as “deluded” and claiming that a second referendum would deliver a larger majority for leave.

In a pantomime moment, Farage turned to those sat behind him to ask whether they really wanted him to return as an MEP. He ended his speech to the parliament by appealing to the EU’s leaders to “get the British out”.

Later in the debate, Tusk hit back, saying: “Mr Farage, you have presented passionate arguments against a second referendum. But the truth is that the second referendum took place in 2016 because the first one took place in 1975. And then a vast majority of the British public decided that the place of the UK was in the European Economic Community.

“No, it was you who thought three years ago that it was possible to organise a referendum to invalidate the previous one. Then please be consistent also today.”

Michel Barnier, the EU’s chief negotiator, also spoke, saying: “No one is trying to steal Brexit from you, no one is trying to undo the vote of the British people” but, he said, the UK would have to bear the consequences of its decisions.

He said the EU’s leaders last week had allowed an extension of article 50 until 12 April to “open the possibility to the UK to shoulder its responsibility – it is now over to this country to shoulder that responsibility”.

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Tusk’s comments came as the British government emailed the 5.8 million people who have signed a UK parliament petition seeking the revocation of article 50. The email informed signatories that “this government will not revoke article 50”.

The European commission president, Jean-Claude Juncker, speaking after Tusk on the subject of Tuesday’s summit, told MEPs he awaited the Commons decision with interest.

“The debate on China was far less complicated than the debate on the UK and I was saying to some of you that if I was to compare Great Britain to a sphinx, the sphinx would be an open book by comparison,” Juncker said. “Let’s see how that book speaks over the next week or so.”

Barnier warned the British government that the Irish backstop, under which Northern Ireland would stay in the single market and the customs union, would continue to form the basis of the EU’s policy to avoid a hard border on the island of Ireland even in the event of a no-deal Brexit.