The President of the European Commission said yesterday it will be harder for EU member states to show a united front as Brexit talks move onto phase two.
Jean-Claude Juncker called the first phase of divorce negotiations, completed in December, "the easiest".
Speaking at an event in Spain hosted by local newspaper El Pais, Juncker said: "It will be more difficult to keep together the 27 EU members states during the second step of negotiations."
The next round of negotiations will focus on nailing down a transition arrangement before a framework for trade talks can be agreed. Britain has argued a comprehensive trade deal can be finalised by the time of the UK's formal exit from the EU in March 2019.
Juncker said multinational corporations will put pressure on individual governments "to say yes to this or that British proposal".
"In the end, we'll have several extras, several exceptions that will make Europe a mess."
Juncker went on to say he wanted the UK to be a "privileged partner" – but this was only when Britain realised it was a British decision to leave the EU and not the other way round.
"Brexit is not a priority, it's not the future of Europe," he said.
"I'm de-building, deconstructing Europe at the moment... and I'm not happy about that."