Brussels should have intervened during the 2016 EU referendum to counter the “lies” spread by Brexit campaigners, a top EU figure has said.
European Commission President Jean-Claude Juncker said the bloc regretted following the advice of David Cameron, who warned about meddling in British politics.
“It was a mistake not to intervene and not to interfere because we would have been the only ones to destroy the lies which were circulated,” he told a news conference in Brussels on Tuesday.
“I was wrong to be silent at an important moment.”
Mr Cameron called the EU referendum and campaigned for Remain, announcing his resignation within hours of Leave’s victory being revealed.
Theresa May replaced him – and her premiership has been dominated by sorting out Brexit.
Cross-party talks involving her government and Labour are due to resume later on Tuesday.
Pressure is growing on the prime minister to reveal a firm date for her departure, amid festering Tory resentment at her leadership.
Mrs May is due to meet with the chairman of 1922 committee of backbench Conservative MPs after a request from the group for “clarity” about her timetable for leaving.
Elements of the party fear she could be about to strike a compromise with Labour that will represent a watered down version of Brexit.
But the cross-party talks appear to be on rocky ground, with shadow chancellor John McDonnell saying at the weekend he has no trust in the prime minister because she has “blown the confidentiality” of the talks.
It followed news reports that she is prepared to offer a temporary customs union with the EU as a way to break the deadlock.
Downing Street rejected the claim, with Mrs May’s official spokesman saying: “I don’t believe that is the case. We have preserved the confidentiality of the talks.”
He added that the cabinet talked about the Brexit discussions for around an hour on Tuesday morning.
“The prime minister said that while an agreement with the opposition had not been reached, the public had sent a clear message in the local elections that they want both of the main parties to get on with delivering Brexit,” the spokesman said.
“She said it was right to continue with the talks process.”
There was a “broad understanding that there is a need to get on with this” at the gathering of Mrs May’s top team, the spokesman said.
Britain was due to leave the EU at the end of March, but the exit date has been pushed back to the end of October.
Mrs May’s struggle to get an exit deal approved by parliament means Britain is on course to take part in European elections almost three years on from the referendum.
There is no formal deadline for the cross-party talks, but it is thought likely that the government will move towards holding indicative votes on Brexit alternatives in the Commons if there is no progress made this week.
The Downing Street spokesman said: “What is absolutely vital is that we find a way forward which can command a stable majority in the House of Commons.
“That’s what the prime minister is working to achieve.”