Brussels’ chief negotiator said the “same significant divergences persist” ahead of arriving in London – with just 35 days left to avoid the huge disruption and damage from the talks failing.
Even Mr Barnier’s decision to get on the train had been in doubt, after the EU suggested London would have to be ready to make key concessions in order to make it worth the journey.
The negotiations remain mired in the familiar disputes over fair competition rules, the mechanism for dealing with future breaches and fishing rights.
Boris Johnson is yet to make the crucial decision whether to compromise – or accept the no-deal that his economic experts warned would delay the recovery from the pandemic by a further year.
Mr Barnier tweeted: “In line with Belgian rules, my team and I are no longer in quarantine. Physical negotiations can continue. Same significant divergences persist.”
The talks will take place on Saturday with David Frost, the prime minister’s pointman, but were expected to be brief, one EU source told the BBC.
Before leaving, Mr Barnier was reported told a closed-door meeting for EU national diplomats that he was unable to say whether an agreement would be reached in time.
However, the European Parliament is arguing it needs several weeks to scrutinise and ratify its terms.
Mr Barnier was also briefing MEPs and holding a video call with EU fishing ministers on Friday, but EU sources have played down any suggestion of a breakthrough.
The UK is demanding annual negotiations on what EU fleets will be allowed to catch in British waters, but the EU wants more certainty and for British gains to be kept to about 15 per cent.
On so-called ‘level playing field’ issues, both sides are committed to maintaining “common high standards”, but the UK opposes having to adjust to future EU rule changes.
Brussels is also seeking a firm mechanism to ensure there are consequences for either side, within the trade deal, if standards diverge in the years to come.
Its position has hardened since the government sought the right to break international law over the implementation of the Northern Ireland Protocol.
Later, in a series of typically hardline tweets, Lord Frost again insisted there would be no agreement unless the EU fully respected the UK’s “sovereignty”.
“That is not just a word - it has practical consequences. That includes: controlling our borders; deciding ourselves on a robust and principled subsidy control system; and controlling our fishing waters,” he said.
“We will continue to work hard to get it – because an agreement on any other basis is not possible.”