London: After months wracking their brains over the headache of the Irish border after Brexit, the UK and EU have trumpeted their ingenious solution.
About 300 million people and 500 million tons of freight cross the border between Northern Ireland and the Republic every year.
Friends visit friends, doctors visit patients, farmers visit customers. Many workers have a home in one country and an office in the other.
The 1998 Good Friday peace agreement was written on the assumption of, and arguably made possible by, both sides of the border being inside the EU.
It meant the border, practically, could melt away. Hundreds of roads now criss-cross it with no signs or fences (one road crosses the border four times in 10 minutes' drive).
Both sides were, all along, in complete agreement: this should stay the case. Nobody wanted border posts running customs and immigration checks: they would be a target for troublemakers.
But there's a big problem.
The UK wants - Prime Minister Theresa May has promised - a Brexit outside the single market and customs union. That means regulations in Northern Ireland would be set from Westminster, those in the Republic from Brussels.
If the UK doesn't have control of its own regulations, it won't be able to sign trade deals - including with Australia.
But once regulations diverge, you need customs checks - somewhere.
Translated from the bureaucrats, the joint report on the Brexit negotiations released on Friday goes as follows:
The UK is opposed to any physical checks or controls on the border.
The UK intends to ensure this can continue as part of an overall future trade and customs arrangement with the EU.
If it can't do that, the UK and EU will have to reach a solution specific to Ireland.
If they can't agree on one, regulations in the whole of the UK will stay in "full alignment" with the rules set by the EU's Single Market and Customs Union, to the extent necessary to protect the 'all-island economy' and the peace deal.
There are two things to note here.
Firstly, that clanking sound you hear is a can being kicked down the road.
Secondly, unless some other, unspecified solution can be found, then the UK will stay aligned with Single Market and the Customs Union rules.
Effectively, this leaves control of the UK's trade laws in Brussels.
So Britain's promised future as a free-trading nation is now hostage to finding a solution to the border conundrum.
All along both sides have promised a "unique" and "creative" solution will be found.
This deal is certainly unique. But the only concrete solution the parties have so far found, after a year and a half's thought, is incompatible with the Brexit that Theresa May had pledged to deliver.
