A "decisive" few days lie ahead when it comes to Brexit.

That was the assessment from European Commission President Ursula von der Leyen on Wednesday (November 25).

Britain and the EU are in a last-ditch effort to agree terms to preserve trade flowing without tariffs or quotas from the start of 2021.

That's when London's transition out of the European Union is supposed to be completed.

"The European Union is well-prepared for a no-deal scenario but of course we prepare to have an agreement. I fully trust in the skilful steer of our (European Union) chief (Brexit) negotiator Michel Barnier. But one thing is clear. Whatever the outcome, there has to be and there will be a clear difference between being a full member of the Union and being just a valued partner."

The head of the EU executive told the European Parliament that major gaps could still lead to a rough split in trade with Britain past December 31st.

An eventuality, she said, the bloc was prepared for.

"The crucial topics for the European side are of course questions linked to the level playing field, the governance and fisheries. And with very little time ahead of us, we will do all in our power to reach an agreement. We are ready to be creative, but we are not ready to put into question the integrity of the Single Market."

It's just five weeks before current EU-UK trading rules expire following Brexit.

But Von der Leyen added that contentious issues remain dividing up fishing quotas and agreeing access to waters.

As well as finding ways to settle future disputes and ensuring economic fair play for companies.

On Tuesday (Nov 24) U.S. President-elect Joe Biden also got involved.

Saying he did not want to see a guarded border between Ireland and the United Kingdom.

Adding that he had discussed the matter with the British prime minister and other European leaders.