EU warns UK to abide by Brexit political declaration

"There has been no significant progress since the start of these talks," Barnier told reporters in Brussels.

"In all areas, the UK continues to backtrack on the commitments is had undertaken in the political declaration," he added.

The UK side sounded more positive, with chief negotiator David Frost saying that although progress was limited, talks had been positive.

This time both sides have refrained from the bitter accusations characterising the previous round of discussions in May.

Negotiators will hold talks again at the end of June or early July, and expect guidance from UK and EU political leaders when they meet later this month.

The UK has stressed it would not seek an extension on the transition period, so talks on the future deal will have conclude this year.

Barnier warned that taking all the ratification processes into account, a legal text needs to be ready by 31 October.

The French politician, however, warned that the UK needs to stick to commitments on preventing unfair competitive advantages, sticking to high standards with regards to state aid, competition, the environment and social issues.

"We cannot continue like this forever," Barnier said.

If the UK sticks to commitments Johnson has agreed to last year, Barnier said it is possible to find common ground during the course of the summer and autumn.

Face-to-face

The EU's insistence on sticking to the political declaration has irked London, which argues that since it is not a legal text, it should be viewed more flexibly.

"They [UK] hyped up the political declaration originally, and ratified it. Now they want to rip it up, and argue that it is not legally binding. This shows a level of reliability," one EU source quipped sarcastically.

Key hurdles between the two sides run deep, while trust has also been on short supply as London is seen as both backtracking and also slow on implementing the arrangements on the Irish border.

The EU wants guarantees to avoid dumping and the UK undercutting the bloc, but London rejects this - perceiving it as being dictated to by the EU.

The sides discussed upholding common standards, and how to increase those standards together, but with little success.

Britain also continued to refuse discussing foreign affairs, development and defence issues, Barnier said.

On fishing quotas, where the EU said an agreement is a prerequisite to a broad trade deal, there has been little progress - although Brussels seemed to try to move away from their original position.

EU countries, such as France, the Netherlands, Ireland and Denmark, which largely benefit from the current system, might nevertheless insist on a tough line.

Barnier reported some progress over human rights guarantees that would allow the UK and the EU to continue cooperating in law enforcement and judicial matters from 2021. But an agreement is still far away.

The EU side said the UK also does not want to engage in an agreement on counterterrorism-financing, and money-laundering, arguing that existing international rules are enough.

A major outstanding issue is how the overall agreement would work, and what legal links could be established between different areas of cooperation to ensure the deal is implemented.

Barnier said he hoped the negotiation at the end of June can continue face to face because it would "work better".