Suggestions by British Prime Minister Theresa May that she will enter bilateral discussions with Dublin on resolving the Irish Border question have been rubbished.
The Government is concerned that the UK is pushing the idea of a potential 'side deal' on what has become one of the most contentious elements of the Brexit negotiations.
Three times during press events to outline the latest UK position on Brexit last Friday, Mrs May referenced talks with Taoiseach Leo Varadkar.
Again yesterday she told the BBC how "pleased" she was that the Taoiseach "has agreed that the UK and Irish governments and the commission can sit down and look in more detail at the proposals that we've put forward".
However, a spokesman for Tánaiste Simon Coveney categorically ruled out the possibility of three-way talks.
"The negotiation to leave the EU is between the EU and the UK. Michel Barnier is the chief negotiator and there will be no bilateral side negotiations," he said.
It is understood Mrs May's narrative evolved from a meeting she had with Mr Varadkar in Belfast last month.
While the two leaders were at Stormont to discuss the obstacles to restoring the Northern Ireland Assembly, the conversation did divert to Brexit.
Sources say Mr Varadkar offered to assist the UK in developing a credible way of preventing a hard Border on the island.
Mr Coveney's spokesman told the Irish Independent that this offer was "in the same way we will help in every aspect of the negotiations, by feeding into the overall process through the taskforce".
"Of course, our important bilateral contacts with the UK as our nearest neighbours continue and we want the least-damaging Brexit, but exit negotiations are not bilateral," he reiterated.
Finance Minister Paschal Donohoe will hold a series of meetings with senior UK politicians today, including Chancellor Philip Hammond and Minister for the Cabinet Office David Lidington.
A statement said the discussions were "part of the regular dialogue between the minister and his British counterpart and will provide an opportunity to review current international economic developments".
Mr Donohoe said: "My visit comes at an opportune time to review recent developments in relation to Brexit ... Ireland has always been clear that we want the closest possible relationship between the EU and the UK.
"In this regard, we will continue to work closely with our EU partners and with the UK on ensuring a good outcome to the Brexit negotiations that sees the impact on our trade and economy minimised."
It comes as Mrs May yesterday described the Border question as a "complicated subject".
"There are various elements of ensuring that we don't have a hard Border between Northern Ireland and Ireland. Part of it is the customs arrangements," she told Andrew Marr on BBC1.
Mrs May dodged a question on Foreign Secretary Boris Johnson's comparison between Ireland and the border line between Westminster and Camden in London.
But she did appear to slap down the former mayor of London when asked about a letter he sent her last week outlining a belief that "it is wrong to see the task as maintaining no Border".
She said: "He's clear that there won't be a hard Border between Northern Ireland and Ireland, and we're working to that. We've got proposals as to how we can achieve that, now we're going to be able to sit down and talk with others about how we do that."
However, Mr Coveney told the same programme that Mrs May needs to spell out her approach. "She hasn't really gone into any more detail than we've already heard in terms of how she is going to solve the problem of maintaining a largely invisible Border on the island of Ireland," Mr Coveney said.
In a statement that will cause further alarm in Downing Street, the Tánaiste said he was "not sure that the European Union will be able to support" the plan.
"While of course we will explore and look at all of the proposed British solutions, they are essentially a starting point in negotiations as opposed to an end point," he said.