[FILE PHOTO: Britain's Prime Minister Boris Johnson leaves Downing Street in London, Britain February 12, 2020. REUTERS/Hannah McKay]Reuters * Boris Johnson threatens to walk away from trade talks with the EU in June if a deal looks unlikely. * The UK government said on Thursday it is prepared to abandon talks in the summer. * Johnson's government published its negotiating mandate for talks with the EU on Thursday. * The mandate confirmed Johnson's refusal to sign up to EU rules as part of a trade agreement. * The EU's chief Brexit negotiator hit back and accused the prime minister of "moving back from" the commitments he made to "free and fair competition" in Brexit negotiations last year. * Visit Business Insider's homepage for more stories. Boris Johnson has raised the prospect a chaotic divorce from the European Union this year after threatening to walk away from trade talks with the Brussels in June if a deal looks unlikely. Johnson's government on Thursday published his negotiating mandate for the next 10 months of talks, setting up a clash with Brussels once negotiations get underway in the next few weeks.SEE THE REST OF THE STORY AT BUSINESS INSIDERNOW WATCH: A law professor weighs in on how Trump could beat impeachment SEE ALSO: * British farmers fear Boris Johnson has 'terrifying' plans to abandon UK food standards in order to win a Brexit trade deal with Trump * The EU will tell Britain that it cannot have a trade deal unless it bans chlorinated chicken * The EU will tell Britain to give back the ancient Parthenon Marbles, taken from Greece over 200 years ago, if it wants a post-Brexit trade deal