European Union leaders are expected to formally agree their Brexit negotiating strategy when they meet for a special summit later.
The 27 member states remaining in the EU once the UK departs will be represented in Brussels for the anticipated ratification of the joint approach they will adopt in the forthcoming separation talks.
Draft proposals outlined by European Council president Donald Tusk were published last month.
There are unlikely to be any radical departures in the final framework, with the EU 27 expected to remain firmly committed to a "phased" approach to negotiations.
Mr Tusk has insisted progress must be made on disentangling the UK from its ties and obligations to the EU before discussions can turn to the shape of any future trading partnership.
Key issues in the first phase are the size of the "divorce bill" the UK will need to stump up on departure - estimated by EU officials at around £50 billion - and addressing uncertainty over the rights of EU citizens living in the UK and British expats residing on the continent.
Mr Tusk has also signalled a desire to resolve the thorny problem of the Irish border - and how to avoid customs and immigrant checkpoints on the politically sensitive frontier - before moving negotiations to the second stage.
In a letter to fellow EU Council members ahead of their Brussels summit, Mr Tusk wrote: "Before discussing our future, we must first sort out our past.
"Only once we collectively determine in the European Council that sufficient progress has been made on all these issues will we be in a position to hold preparatory talks on the future relationship with the UK.
"I would like us to unite around this key principle during the upcoming summit so that it is clear that progress on people, money and Ireland must come first."
Aside from dealing with the present day Irish border, the European Council may also address its approach if the day came when the people of Northern Ireland voted to end partition and join a united Ireland.
EU leaders are ultimately expected to agree that, in such circumstances, Northern Ireland would automatically assume the EU membership already held by the Republic of Ireland, rather than having to reapply.
One of the more controversial elements of Mr Tusk's draft guidelines in March was a suggested veto for Spain on any future UK/EU agreements that involved Gibraltar.
Another recent issue of contention that could feature on Saturday is whether a free trade deal would include the financial services industry and, if it did, whether City of London institutions would still be bound by Brussels oversight.