European Union Brexit negotiator Michel Barnier is in London for informal talks with his UK opposite number, David Frost.
The two negotiators are meeting ahead of the resumption of formal negotiations next Monday.
The European Commission says today's meeting was scheduled.
The principal negotiators have usually opened each round with an informal meeting at top level, but this time that meeting is taking place almost a week before the formal talks take place.
With the transition period for Britain's departure from the EU due to end on 1 January, the time left to strike an agreement on the future relationship between the UK and EU is effectively between now and the next EU summit in mid-October.