The European Union has warned that Britain will have less than 18 months to strike a deal to exit the bloc once Brexit negotiations begin, assuming London keeps a promise to formally launch the process of leaving the EU by the end of March.
At a news conference on Tuesday in Brussels, the EU’s chief Brexit negotiator, Michel Barnier, set a target of agreeing a Brexit deal with Britain by October 2018.
Barnier said the two-year deadline for final withdrawal stated in Article 50 of the EU treaty meant there would be less than 18 months for actual negotiations because it will take several months to have a deal ratified by the UK, the other 27 EU states and the EU parliament.
Once article 50 is triggered by an EU member state, there is a two-year time limit to complete negotiations. If negotiations fail to reach agreement, the member state leaves the bloc with nothing.
"Time is short," he said. "Should the UK notify the European Council by the end of March 2017 ... it is safe to say negotiations could start a few weeks later and an Article 50 agreement reached by October 2018."
British Prime Minister Theresa May has said she will give formal notification of Britain's departure in March. May's spokesman said she was not expecting to negotiate a Brexit deal for longer - something that would be possible only by mutual consent.
"There is a two-year time frame," the spokesman said after Barnier's remarks. "We are not seeking to extend that process."
Barnier said a Brexit will not be a better deal for the UK than staying in the EU and London could not "cherry pick" on issues such as the EU single market.
"Keep calm and negotiate,” Barnier said. “The work will be legally complex, politically sensitive and will have important consequences for our economies and first for our people on both sides of the channel.”
May faces a rebellion among her own lawmakers when Parliament will debate on Wednesday whether the government should make public its Brexit plan before triggering formal divorce talks with the EU.
The opposition Labour Party has put forward a motion, calling on the government to publish its plan for leaving the bloc before it invokes Article 50.