By luck or design the breakthrough in Northern Ireland, facilitated by the easing of customs controls, came on the same day that trade between the EU and the rest of the UK became a whole lot more complex and costly.
The government's imposition of long-delayed Brexit border controls, starting with health certificates for food and flowers, emphasised just how hard it has been to make the same controls disappear for Northern Ireland.
Northern Ireland's dual status both within the UK but the EU Customs Union was a necessary compromise to secure a hard Brexit and a soft land border on the island of Ireland.
But as the measures imposed on British business today demonstrate, Customs Union membership usually comes at the price of strict controls designed to protect biosecurity and the common market.
So while Andrea Leadsom, today a junior health minister but in 2016 a prominent Brexiteer, was dismissing the £330m price of new customs controls as a cost business just had to swallow, her colleague Chris Heaton-Harris was heralding the removal of the same checks at the GB-NI border.
Those checks, which made the Irish Sea border real, were the pretext for the DUP to walk out of Stormont.
Convincing the party they can be removed was the key to winning its return.
The command paper published on Wednesday suggests that some, but not all, of the paperwork and physical checks have been removed.
First the easy part.
The government says there will be no "UK processes" for goods moving from NI to GB, though goods making the same journey via Dublin will need an EU customs declaration.
In essence this is the same regime that applied until yesterday to any imports from the EU into the UK. Goods moving from Dublin to GB, however, will face the full range of new customs processes.
The trickier route has always been goods moving from GB to NI, and here there are some changes to the Windsor Framework.
A planned green lane - perhaps ill-named in hindsight - is replaced with a UK Internal Market lane, for which a guaranteed 80% of all freight will be eligible as long as the goods are not "at risk" of moving into Ireland, and therefore the EU.
A red lane alongside will deal with at-risk goods, and all physical "identity checks" will be focused on this route. The only physical checks on the UK market lane will come if criminality or abuse is suspected.
And while the government says it aims to eliminate all physical checks, customs processes for animal and plant security - sanitary and phytosanitary checks in the jargon - will remain however, though the paper is vague on what these will entail.
"The United Kingdom has also made written guarantees on biosecurity to the European Union, including that we will protect against disease risks to the island of Ireland, and we would of course always take any action needed to meet those commitments," it states.
There is also a commitment to remove all customs paperwork from GB-NI trade, but that is not the same as no paperwork, and there will be processes for those shipping goods that do not apply for trade across the Welsh or Scottish borders.
The command paper says this paperwork will be much less burdensome, with a "shorter, simpler dataset" of "standard commercial information."
To demonstrate the commitment to remove physical checks, a planned border control post at Cairnryan, the main freight port for goods coming from Great Britain, will not be built.
It remains to be seen if the minutiae of trading arrangements withstands the scrutiny of sceptical unionists and Brexiteers, and we can never know if the deal announced today would have delivered Theresa May a Brexit majority back in 2017.
But ministers do believe the deal gives Northern Ireland a unique position they want to exploit, enjoying both unfettered access to the UK internal market and the EU customs union.
There will be more than the odd business elsewhere in Great Britain facing import costs for the first time today, wondering why they can't have the same.