A spokeswoman for the European Commission said "technical talks" were continuing on the diplomatic process but she had no progress on substance to report.

The comments came as Prime Minister Boris Johnson insists he will take Britain out the bloc with or without a deal on October 31 and rebel British MPs try to stop him.

"Our working assumption is that there will be Brexit on October 31," Commission spokeswoman Mina Andreeva told reporters.

Asked whether it was possible that Britain and Europe would part ways without an agreement, she said: "I would say that it is a very distinct possibility."

Britain's Brexit "sherpa", senior diplomat David Frost, is due in Brussels on Wednesday for talks with EU officials.

But Andreeva could offer nothing to dispel reports from London that Johnson's government has yet to come up with a way to modify a previously agreed withdrawal accord that Johnson has rejected as unacceptable.

"At this stage I can't report any concrete proposals having been made that we have seen. Having said that, we are not insisting on having anything on paper, it can be digital as well," she said.

Asked whether Britain had been able to provide a "sketch" outline of how they would like to see the withdrawal agreement change, Andreeva said could not report even "scribbling on cigarette packets".

Commission chief Jean-Claude Juncker and Brexit negotiator Michel Barnier are due to report to senior EU officials on Wednesday on progress in the talks and on EU preparations for a "no deal" divorce.