Bernd Lange, the German MEP who chairs the parliament’s international trade committee, warned “a deal has to be done before 31 October”.
The announcement is a blow to hopes of a late agreement breaking the deadlocked negotiations.
Negotiators are due to meet in London next week for their eighth round of talks, but both sides have suggested the prospect of any serious movement is remote.
This week, the government was warned by freight operators of the potential for border chaos in January, with supermarket supply chains expected to be hit if issues cannot be sorted in four months’ time.
“This is a crucial negotiation round,” said Mr Lange at a seminar organised by the European parliament. “It’s totally clear the clock is ticking: we’ll have time until the end of October, and then the text has to be ready.
“It’s totally clear that if there will be a deal this has to be done before 31 October at the latest, and therefore we need some progress in this negotiation round because up till now there is just really really little progress; and in the main area, there is nothing.
“This is not a simple text, a comprehensive trade agreement has a volume of around 500 pages, and this has to be legal script and translated, and then of course scrutinised by the European parliament. This also needs time.”
Mr Lange warned that time pressures were particularly acute because talks had not even progressed to a stage where both sides had their own working legal texts that could be merged into a “consolidated” compromise.
He said: “Normally in trade negotiations, step by step, time by time, we have so-called consolidated texts where we merge the proposal from both sides in one text. This exercise is not there at the moment. We have just one time to do all this really important work and therefore more or less the decisions on the future on UK-EU trade relations is taken next week.”
If Boris Johnson dreams of clinching a Brexit deal at a last-minute negotiation with EU leaders, he is likely to be seriously disappointed
EU source close to talks
Mr Lange continued: “For us, the parliament has a deadline of 31 October. The text has to be ready otherwise we have no chance to go into the ratification progress. So next week, starting 8 September, probably we will have second negotiation round in October, but it’s a really tough timetable and I don’t expect that it’s really possible.”
Similar warnings about time were issued around the withdrawal agreement, and officials close to the process point out that while that treaty was agreed in mid-October 2019, the lengthy ratification process meant that the UK ended up leaving the bloc at the beginning of February 2020.
“They need November and the first two weeks of December for scrutiny, legal scrubbing, translation, committee reports,” one EU source close to the process told The Independent.
“Maybe it could stretch to early November, but that would really be putting the ratification system under severe strain.”
The source added: “If Boris Johnson dreams of clinching a Brexit deal at a last-minute negotiation with EU leaders, he is likely to be seriously disappointed. The risks of failure grow with every day that passes.”
Very little actual progress has been made since negotiations on trade kicked off in the spring. Officials on both sides say the coronavirus crisis has deflected political attention elsewhere and made it more difficult to make the major political calls needed to come to a compromise.
Major sticking points remaining include the issue of EU fishing fleet access to UK waters, the extent of UK alignment to EU standards and regulations, and the overall legal governance of the deal.
But it is specifically the issue of whether Britain will follow EU state aid rules that has proved the most contentious, amid reports that Boris Johnson wants to the UK to be able to fund its national champion industries.
With the end of October as the deadline, the last major set piece for Brexit drama in Brussels will be the European Council meeting scheduled for 15 and 16 October, where the bloc’s 27 EU leaders will meet.
The meeting could provide breathing space for the EU to reassess its own positions – though EU sources say an intervention may not be on the cards, with other issues such as the coronavirus recovery to discuss.
David Frost, the UK’s chief negotiator, said his team would “negotiate constructively” but that “the EU’s stance may, realistically, limit the progress we can make next week”.
A Downing Street spokesperson said: “Our goal remains to reach an agreement and we’ll continue to work hard to do that. We’re clear there’s lots of work still to be done. We need more realism from the EU and for them to show they understand the fundamentals of our position as an independent country.”