A document expected to be released as Dominic Raab makes his first visit to Brussels as Brexit Secretary warns of the possibility of long queues at borders and ports, disruption to planes and new restrictions on data transfers.
Meanwhile, dozens of documents setting out the preparations business will need to do in a “no deal” Brexit will be published over the coming weeks.
Theresa May told MPs on the Commons Liaison Committee that around 70 “technical notices” would set out what is required for citizens and firms if the UK leaves the EU in March next year without a withdrawal agreement.
A draft copy of the 15-page European Commission leaflet on potential shocks, obtained by the BBC, states that it is the responsibility of each individual nation and institution in the EU to hire staff and make arrangements to deal with the UK crashing out without a deal.
The document is expected to warn that preparations must be stepped up immediately at all levels to take in all possible outcomes, listing potential problems in areas including borders, transport, data and movements of medicines.
Mr Raab’s talks with the EU’s chief negotiator come as the Government attempts to try and steady its withdrawal strategy after two weeks of turmoil, including the resignation of his predecessor David Davis in protest at Prime Minister Theresa May’s Chequers Cabinet compromise on withdrawal aims.
The meeting comes as Tory former Cabinet minister Lord Chris Patten predicted there could be an emergency Brexit general election in the autumn.
Lord Patten told BBC2’s Newsnight: “It is perfectly possible that this autumn and winter we will find that Parliament can’t move forward, can’t move back, can’t move sideways and that we are faced with chaos and crashing out of the European Union.
“I don’t remotely discount that possibility.
“So, I don’t either discount the prospect of us finding ourselves in a general election during the course of the autumn and winter.
“If I was still party chairman... I would certainly be thinking about starting to book some advertising hoardings just in case.”
Mrs May makes her first visit to the Irish border since the referendum on Thursday.
Dealing with post-Brexit cross-border trade remains a crunch issue in the withdrawal negotiations, and a source of tension in Tory ranks.
The talks follow an extraordinary fortnight for the Government in which the Cabinet agreed a compromise deal on Brexit only for Mr Davis and Boris Johnson to quit Mrs May’s top team as a result.
After Mr Johnson used his resignation statement in the Commons to call for the PM to abandon her “miserable” version of Brexit, Mrs May’s former joint chief of staff Nick Timothy said the current situation was “deeply depressing”.
Writing in the Daily Telegraph Mr Timothy said that if Britain leaves the EU in “chaos” or does not leave the bloc at all, “a national humiliation greater than Suez awaits”.
The comments come after Mrs May survived a series of knife-edge Commons votes which had the potential to sink her fragile premiership.
The PM received a boost at a meeting of the backbench 1922 Committee when Eurosceptic MP Simon Clarke said he had changed his mind about trying to topple her.
Mr Clarke said he had withdrawn a letter calling for a confidence vote in Mrs May because Brexit had taken the Tory party to “breaking point”, stating: “We have looked into the abyss in the last few days.”
In order to boost support for her Brexit stance, Mrs May is to hold a series of meetings with grassroots Tories over the summer, according to reports.