A post-Brexit transition period is "not a given", the European Union's (EU) Brexit negotiator Michel Barnier warned Britain on Friday, saying London had raised "substantial" issues with the plan proposed by the bloc.
Barnier, speaking to journalists in Brussels after the latest round of negotiations with British envoys, said he was surprised by London's position and that some of the EU's positions on the transition period were non-negotiable.
"If these differences persist, a transition is not a given," Barnier said.
"If these disagreements were to persist, there will undoubtedly be a problem. I hope we will be able to resolve these disagreements in the next round."
"The sooner the UK makes its choices, the better," Barnier also said of the EU's expectation that London should present its vision of its new relationship with the bloc after the post-Brexit transition ends.