The European Parliament's Brexit negotiator warned his British counterpart on Tuesday that there is an "intense" window of just 15 months to complete talks for the country's exit from the EU.
Guy Verhofstadt said he had also told Brexit minister David Davis that European lawmakers would not accept Britain trying to keep access to the single market while limiting freedom of movement for EU citizens.
Former Belgian prime minister and leading European federalist Verhofstadt had tweeted that it would be a "hell of a meeting" after Davis jokingly compared him to Satan earlier this year.
"We agreed on some things, on the need for this process to start as early as possible and need to be finished in any case before the next European elections" in May 2019, Verhofstadt said after the talks in Strasbourg, France.
"So the window for the negotiations is more or less 14, 15 months," he added. "It's going to be a period that is very intense."He said if Britain triggers the two-year divorce process in March 2017 as Prime Minister Theresa May has promised, then formal negotiations are unlikely to start until May 2017.
MEPs must then formally give their consent for any deal and that would take several months from late 2018, he said.
Verhofstadt added that it was "impossible to find solutions where we destroy the so-called four freedoms" including the freedom of movement.