The European Commission said “everyone must now step up preparations for all scenarios and take responsibility for their specific situation” ahead of Britain’s official exit day of 30 March 2019.
It warns of the possibility of long queues at borders and ports, disruption to air travel and new restrictions on data transfers if no exit deal is agreed between London and Brussels.
“Today’s text calls on member states and private parties to step up preparations and follows a request by the European Council last month to intensify preparedness at all levels and for all outcomes,” the bloc’s executive said.
“While the EU is working day and night for a deal ensuring an orderly withdrawal, the UK’s withdrawal will undoubtedly cause disruption – for example in business supply chains – whether or not there is a deal.”
It added “there is still no certainty that there will be a ratified withdrawal agreement in place on that date”.
On the prospect of Britain exiting the EU without a deal, Prime Minister Theresa May’s official spokeswoman said the progress made so far in the talks suggests “that is not where we will end up”.
The release of the European Commission’s leaflet comes as the new Brexit Secretary Dominic Raab heads to Brussels for talks with Michel Barnier, the EU’s chief Brexit negotiator.