The European Union’s chief Brexit negotiator, Michel Barnier, handed British Prime Minister Boris Johnson an ultimatum, warning there will be no trade deal unless the U.K. agrees to the bloc’s demands on fair competition and fishing.

“The trade deal will be associated with a fisheries agreement and a level playing field, otherwise there won’t be any agreement at all,” Barnier told reporters in Brussels on Tuesday. “If we want to achieve in the short period demanded by Mr. Johnson, we can’t have backtracking.”

Michel Barnier
Michel Barnier

He spoke days before the two sides are due to open formal trade negotiations that will decide whether Britain will continue to enjoy tariff-free access to the bloc’s single market. If the two sides fail to reach agreement by Johnson’s year-end deadline, Britain will default to trading with the EU on terms set by the World Trade Organization, meaning the return of tariffs and quotas.

In a response to the EU’s negotiating mandate, Johnson’s office said it will seek to prioritize Britain’s legal freedom from the bloc. The EU respected the autonomy of Canada and Japan when signing trade deals with those countries and U.K. just wants the same, Johnson’s office said in a statement.