After a slow start to negotiations to unravel more than 40 years of union, Prime Minister Theresa May’s government is keen for the discussion to move beyond the EU’s focus on a divorce settlement to consider how a new relationship could work.

But the bloc has repeated that before there is “sufficient progress” in the first stage of talks on the rights of expatriates, Britain’s border with EU member Ireland and a financial settlement, officials cannot consider future ties.

Last month, the EU’s top Brexit negotiator Michel Barnier told ambassadors from the 27 countries that will remain in the bloc that talks on future ties were less likely to start in October.

“Government officials are working at pace and we are confident we will have made sufficient progress by October to advance the talks to the next phase,” a spokeswoman for the Department for Exiting the European Union said in a statement.

“As the Secretary of State (Brexit minister David Davis) has said, it is important that both sides demonstrate a dynamic and flexible approach to each round of the negotiations.”

On Wednesday, unidentified sources were quoted by Britain’s Sky News as saying the two sides might have to delay talks on their post-Brexit relationship until December because they would not make the progress required by the EU.

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Britain published proposals for the border between Ireland and the province of Northern Ireland on Wednesday, saying there should be no border posts or immigration checks to avoid a return to a ‘hard border’.

It was aimed at tackling one of the most difficult aspects of the talks and was welcomed by the Irish government.

But perhaps a more tricky part of the talks is how much Britain should pay the EU when it leaves in March 2019. While saying it will meet its responsibilities on the so-called Brexit bill, Britain has also questioned some suggestions from the EU that it must pay around 60 billion euros.