Negotiators from the UK and EU are having what has been described as “intense technological discussions” in an attempt to agree a brand-new Brexit deal.
About a dozen British officials, including the UK’s EU adviser David Frost, are taking part in the talks at the EU Commission in Brussels.
The powwows are expected to continue through the weekend.
But European Council President Donald Tusk has suggested there is only the slightest probability of an agreement.
The UK is due to leave the EU at 23:00 GMT on 31 October and a European leaders’ elevation next Thursday and Friday is seen as the last chance to agree a transaction before that deadline.