Leaders from the hardcore Brexit-supporting wing of the Conservative Party, the European Research Group [ERG], are meeting the EU's chief negotiator Michel Barnier on Monday.
Iain Duncan Smith and Owen Patterson will be joined by Lord Trimble, the former leader of the Ulster Unionist Party and a veteran of the negotiation team which struck the Good Friday/Belfast agreement.
A key element of that agreement was that the border between Northern Ireland and the Republic of Ireland remained open, frictionless and, in practice, invisible.
The delegation's leader, Mr Patterson, said: "We will be discussing the European Research Group paper which I have already sent Michel Barnier.
"Using existing techniques, existing processes within existing EU law, we can ensure the integrity of the EU Single Market and Customs Union is not infringed and that near frictionless trade can carry on at all our borders, including Northern Ireland, without new infrastructure on any borders."
The ERG delegation is going around the back of the government's negotiating team, certainly behind the back of the Prime Minister.
Theresa May told The Sun newspaper that the finishing line is within sight in the race to sign a Brexit deal before the end of the year.
If you wanted proof that the talks were in trouble, then it's yet another statement suggesting a deal is close.
In the last few weeks, I've lost count of how many times we've been told the government is within reach of a deal.
EU leaders have said similar, including Mr Barnier waving a draft agreement in the air and saying it was 85% done and that UK ministers have made positive noises.
In fact, 100% of a deal was ready to be signed eight days ago but the Prime Minister ordered her Brexit Secretaryto rush to Brussels, where he arrived on a Sunday afternoon, after minimal notice, and promptly shoved a stick in the spokes of the agreement.
The timetable had been to sign the agreement on the Monday and seal the deal at the EU Summit last Wednesday. It didn't happen. So near and yet so far.
Mrs May is expected to tell MPs on Monday that the deal is 95% done.
Problem is, the remaining 5% just happens to be 100% of a massive problem: the Irish border issue.
Otherwise known as the 'backstop': part of the protocol within the agreement that ensures there can never be a hard border after the UK leaves the EU.
The EU 'backstop' is a suggestion that if the UK leaves without a trade deal that preserves an open border, then Northern Ireland would effectively stay in the EU while the rest of the country leaves.
The PM has vowed never to allow the UK to be carved up by a Brexit deal.
The Unionist parties in NI are, obviously, extremely against any such outcome.
In some ways it is incredible that negotiations are jammed by this backstop stand-off. Nobody involved in the talks wants a hard border and yet nobody can agree on the way to protect the UK's Good Friday Agreement and the EU's single market.
It doesn't matter how much you talk this deal up and how close it is to being done, the blockage over the border has been a barrier to Brexit for over a year now.
The talks remain in a dead end and neither the UK nor the EU seem able to find reverse gear.