The Commission, which is negotiating with London on behalf of the remaining 27 EU members, has said it will engage with Britain on any constructive proposals. German Chancellor Angela Merkel suggested last week that Britain should present a solution to the Irish border question within 30 days.

"I am not aware of any 30 day deadline ... For us, of course, the earlier the better because our working assumption is that Brexit should happen on the 31st of October," a Commission spokeswoman told a daily news conference.