Michel Barnier appeared to play hard ball with the Prime Minister ahead of a fourth round of trade talks this week as he insisted the prospect of a no-deal end to the transition period this year would be compounded by the impact of the Covid-19 crisis.
Mr Barnier told The Sunday Times there would not be an “agreement at any cost”.
With talks on future trading arrangements seemingly in deadlock over issues like fisheries, Britain has only until July 1 to seek an extension to the transition period.
Mr Johnson has repeatedly insisted that the UK will end the transition arrangement on schedule at the end of the year,
However, Mr Barnier accused Britain of not keeping its commitments.
“The UK has been taking a step back – two steps back, three steps back – from the original commitments,” the EU’s chief negotiator said.
“The UK negotiators need to be fully in line with what the Prime Minister signed-up to with us.
“Because 27 heads of state and government and the European Parliament do not have a short memory.”
Mr Barnier said the EU’s heads of state remembered “very clearly the text which we negotiated with Boris Johnson”.
“And we just want to see that complied with. To the letter… and if that doesn’t happen there will be no agreement,” he told the paper.
Mr Barnier insisted UK withdrawal from the EU was a “lose-lose” for both sides, saying no-one – not even Nigel Farage – had shown there was any “added value” to the UK’s departure.
He said, therefore, the natural next step in trade negotiations was “damage limitation”, and if no agreement were reached that would result in “even more consequences” at the worst time possible, given the coronavirus pandemic.
“So, I think we have a joint responsibility in this very serious crisis, which affects so many families… with so many deaths, so many sick people, so many people unemployed… to do everything we can to reach an agreement and I very much hope that we will do so,” he said.