Early Brexit talks to recognise right of North to return to EU in event of united Ireland
European leaders are to acknowledge the potential for a united Ireland in a move that will allow the six counties automatically back into the EU if reunification occurs.
The recognition of a special status for Northern Ireland will be based on the situation which followed the collapse of the Berlin Wall in 1990.
Sources say the guarantee of membership will be tied in with an acknowledgement that the terms of the Good Friday Agreement must be factored into any Brexit deal.
Wording on the commitment is still being finalised, but it is expected to be in documents accompanying the formal EU negotiating guidelines tomorrow.
The development is likely to be promoted as a coup by the Irish Government.
However, the idea of Irish unity remains very sensitive for the UK government, which is also facing the prospect of a second referendum on Scottish independence.
Under the terms of the Good Friday Agreement, Northern Ireland can join the Republic if such a move is supported in a vote both north and south of the Border.
European leaders will discuss the parameters of the forthcoming Brexit negotiations with the UK tomorrow.
The formal guidelines will acknowledge the "unique circumstances on the island of Ireland" and the fact "flexible and imaginative solutions will be required" around the Border.
One political source said there was also an expectation that Taoiseach Enda Kenny could return from the summit with a guarantee the overall 'Irish question' will be resolved early in the two-year Brexit process.
"That may well be the springboard for Mr Kenny to outline his plans to leave office," the source said.
Ireland's case got an extra boost yesterday when German Chancellor Angela Merkel told the Bundestag the "shared space" between the UK and the Republic of Ireland needed to be held together.
Brussels diplomats say special recognition for the importance of the 1998 Good Friday Agreement is certain to happen, and there is also optimism that the EU may continue its grant aid to help underpin the North's fragile peace for some years to come.
"The EU is heavily invested in peace in Northern Ireland. It is unlikely they would want to risk just walking away," a source told the Irish Independent.
There was also talk of people in Northern Ireland continuing to enjoy benefits of EU citizenship.
On trade there is likely to be recognition of the extra costs facing Ireland for the high volume of exports which cross Britain en route to mainland Europe.
It is expected the common travel area between the two islands can be preserved.
Mr Kenny said yesterday the aim for this weekend was to agree on "a base document".
The real negotiating will begin some time after the June 8 British elections.
The EU is insisting the 'exit payment' to be made by the UK must be the first item on the agenda.
Some estimates put the bill as high as €60bn to cover London's existing commitments to EU spending.
In an interview with the 'Financial Times' today, Foreign Affairs Minister Charlie Flanagan says an immediate row over the bill would shunt the negotiations into a cul-de-sac that would overshadow other issues.
"I would say to my European colleagues, don't get hung up on the magnitude of the cheque," he said.