EU chief Brexit negotiator Michel Barnier | Francois Walschaerts/AFP via Getty Images Barnier tells UK to accept ECJ jurisdiction EU’s chief Brexit negotiator compared British delays to ‘a game of hide and seek.’

The EU's chief Brexit negotiator, Michel Barnier, today warned the U.K. that it must accept the jurisdiction of the European Court of Justice in order to achieve a successful withdrawal treaty and transition period when leaving the EU.

“We cannot accept that a jurisdiction other that the Court of Justice of the European Union determines the law and imposes its interpretation on the institutions of the Union,” Barnier said in prepared remarks at a meeting of EU law experts in Lisbon.

He stressed there is little time to waste if a deal on a future trading relationship is to be hammered out successfully before the U.K. leaves the bloc next year.

"If we want to put in place the foundations for our future relationship before the exit of the U.K., we must accelerate," he said, adding that Europe still required "more clarity" from London on a number of issues linked to its future trading relationship and comparing British delays to "a game of hide and seek."

Barnier also criticized British opposition to the EU's position as a "blame game," saying London had to face the fact that the U.K. could not retain membership to a number of EU programs after Brexit.

The U.K. said Wednesday it will accept the jurisdiction of the European Court of Justice in order to participate in EU programs post Brexit.