BRUSSELS: The European Union’s chief Brexit negotiator said Wednesday that Britain should have less than two years as a transition period after it leaves the European Union and that the UK would have to live by all the key EU principles.

Michel Barnier said that the “logical end” of a transition period must be December 31, 2020, giving Britain enough time to adapt to its situation outside the EU and not too long to create further problems.

The transition period would amount to three months less than what Britain initially sought but the date dovetails with the beginning of a new multiannual budget which would leave Britain totally out of it.

Barnier said that “there will be no transition a la carte. All the rules and policies of the EU must continue to be applied.”

That would include the freedoms of people, services, goods and money to move between the member states and allow for the European Court of Justice to have continued clout in Britain during that period.

On top of that, Barnier said that “all new rules adopted by the EU during the transition will be applied to the United Kingdom,” with the EU’s highest court continuing to have authority.

Any full decision will still have to be negotiated between Barnier and British counterpart David Davis. The United Kingdom is set to leave the EU on March 29, 2019.

But Barnier insisted that the negotiations must be concluded months before that, likely in the fall of next year.

“Time must be left from October 2018, a number of months — October to February — for the European Parliament, the (European) Council, the British authorities, the British Parliament, the time to decide about this agreement.”

From March 2019, the EU wants to ensure that its rules apply during any interim period.

“There will be no transition a la carte. All the rules and policies of the EU must continue to be applied,” Barnier said.

Last week, the EU and Britain agreed that there was enough progress in negotiations so far to open them up to future relations and a trade deal.