It is “not acceptable” for the UK to control immigration after Brexit and throughout the so-called “transition period”, the European Parliament’s Brexit coordinator has said.

There will also be a “crisis in British politics” if the British Parliament votes down any Brexit deal agreed by Theresa May, said Guy Verhofstadt, predicting another general election.

Speaking to the BBC’s Andrew Marr Show, he said a trade deal would not be finalised before the divorce date and insisted no changes could be made to fee movement rules during the transition period.

“It’s not acceptable for us that rules will continue without change for financial services, for goods, for whatever other business and only for the citizens their situation will change,” he said.

Michel Barnier, the European Commission’s chief Brexit negotiator, has also been pushing for mass migration to continue after Brexit, contradicting an agreement struck with the UK in December.

Last month, a report found that a million more EU migrants could come to the UK and settle permanently if free movement is extended for two years.

Mr. Verhofstadt also claimed that a tailor-made trade deal would not be possible after Brexit, and said the UK would have to remain inside the Single Market for financial services to continue as they are now.

On the transition period, he added: “I think what is possible by the 29th of March of next year, if everybody agrees with it, the British parliament, European Parliament, will be the withdrawal agreement. Inside that withdrawal agreement also an agreement on the transition.

“The transition for example of two years, at the end of 2020 or the beginning of 2021. And the third thing that will be possible is an annex, a political declaration describing, more or less in detail I should say, the future – what the future relationship will be.

“And then we will use the transition period to clarify this political declaration in an international agreement.”