The EU would consider a potential British request for closer post-Brexit ties than London has sought so far, but will not renegotiate the withdrawal agreement rejected by parliament, its Brexit negotiator said on Wednesday.

Addressing the European Parliament on Wednesday, EU chief negotiator Michel Barnier indicated that one way forward would be for Britain to accept closer alignment with EU regulations to secure a very close trading relationship. EU officials say London could, for example, abandon its determination to leave the EU customs union and centrally regulated single market.

“If the United Kingdom chooses to let its red lines change in future, and that it takes this choice for its advantage of the ambition of going beyond a simple but not negligible free trade accord, then the European Union would be ready immediately to ... respond favorably,” Barnier said.

EU leaders lined up to again rule out any significant change to the binding withdrawal agreement they struck with May last month and that was crushed the previous evening by British lawmakers on opposing sides of the bitter Brexit divide.

However, the sides have also negotiated a separate, non-binding political declaration which spells out their future aims. Asked if Barnier was suggesting reworking that outline of future ties, the EU executive's chief spokesman told reporters: “The withdrawal agreement – and, I repeat, the withdrawal agreement – ... is not open for renegotiation.”

EU officials say staying permanently in the EU customs union or even the full single market would greatly limit disruption on Northern Ireland's EU land border and so ease arguments over the EU's insistence on an “Irish backstop” protocol in the withdrawal agreement that many British lawmakers abhor.

With just 10 weeks to go until Britain's two-year deadline for a deal or no-deal exit, Union politicians were less sanguine than investors. Markets reflected views that stalemate may keep Britain in the EU beyond March 29, or even forever. But Barnier and others warned that the risk of a disorderly departure into a chaotic legal limbo was now greater than ever and that it was a priority for other European countries to prepare for the worst.

It would be wrong for Britain to think the European Union will blink on Brexit and make concessions that undermine its core principles, such as the integrity of the single market, an official at the French presidency said on Wednesday.

"If there's an idea going round that the European Union has shown a firm front but in fact is weak and febrile when it comes to its fundamental principles, well that would be wrong," said the official at President Emmanuel Macron's office.

The date of Britain's exit from the European Union can be postponed, but London would first have to make clear what it would need that time for and what the benefit would be, German Justice Minister Katarina Barley said on Wednesday.

(Cover: European Union's chief Brexit negotiator Michel Barnier delivers a speech during a debate on Brexit after the vote on British Prime Minister Theresa May's Brexit deal, at the European Parliament in Strasbourg, France, January 16, 2019. /Reuters Photo)