BRUSSELS, Sept 16 — EU chief Ursula von der Leyen complained today that hopes of a post-Brexit trade deal are fading and warned Britain not to unilaterally modify the withdrawal deal.

"With every day that passes, chances for a timely agreement do start to fade,” the president of the European Commission said in her annual State of the European Union address.

"Negotiations are always difficult, and we are used to that... But talks have not progressed, as we would have wished. And that leaves us very little time.”

Von der Leyen warned the attempt by Prime Minister Boris Johnson to override parts of the withdrawal treaty he signed last year is illegal and unacceptable.

"This withdrawal agreement took three years to negotiate,” she said. "And we worked relentlessly on it line by line word by word, and together we succeeded.”

The result "guarantees our citizens rights, financial interests, the integrity of the single market and crucially, the Good Friday Agreement,” she said. 

The European Union and Britain "jointly agreed it was the best and only way to ensure peace on the island of Ireland. And we will never backtrack on that,” von der Leyen said.

"And this agreement has been ratified by this house and by the House of Commons,” she told the European Parliament.

"It cannot be unilaterally changed disregarded or misapplied. This is a matter of law and trust and good faith.” — AFP