Late on 7 December, Michael Gove and Maros Šefčovič posed for a picture, smiling beneath their masks, on the fifth floor of the European Commission headquarters in Brussels.
"Pleased to announce that thanks to hard work, Michael Gove and I have reached an agreement in principle on all issues re the Withdrawal Agreement," the Commission vice-president tweeted. "This will ensure it is fully operational as of 1 Jan..."
Gove and Šefčovič had reason to be relieved. They had just spent 12 hours locked in negotiations to grind out the final compromises on how the Protocol would be implemented.
It drew a line under a year of acrimony, during which Boris Johnson had threatened to break international law with the Internal Market Bill, and there were (unfounded) allegations the EU would impose a food blockade on Northern Ireland.
Michael Gove hailed the deal in the House of Commons. It would "keep goods flowing between Great Britain and Northern Ireland in January and provide some necessary additional flexibilities. It protects Northern Ireland's supermarket supplies."
The UK dropped clauses 44, 45 and 47 of the Internal Market Bill. The Gove-Šefčovič breakthrough offered hope that if Northern Ireland could be sorted out, surely an EU-UK trade deal would not be far behind.
Just six weeks later, staff implementing the Protocol at Northern ports have been withdrawn due to intimidation, the DUP has cut all cooperation with Dublin on the Protocol, and Boris Johnson has threatened to trigger Article 16 "to avoid a barrier in the Irish Sea".
The Protocol has certainly been challenging from day one. On 13 January, Gove told the Commons these were teething troubles. "As with any new trading arrangement, the protocol undoubtedly generates challenges as well as providing solutions," he told MPs.
Freight volumes into Northern Ireland were normal, there had been no significant queues, and "supermarkets are now generally reporting healthy deliveries of supplies into Northern Ireland".
However, the events of Friday, 29 January have changed everything. The fallout from the Commission's attempt to trigger Article 16 of the Protocol have been well documented.
However, senior EU figures suspect London is now using the Article 16 fiasco, and even the intimidation of staff at Larne and Belfast ports, as a pretext to mount an assault on the Protocol.
UK sources put it another way. Yes, there were elements in unionism that were prepared to make the Protocol work, but the Commission’s move has caused such a backlash that the political dynamic has changed, and the intimidation of EU and Northern Ireland customs and veterinary staff are part of that.
"There are different views as to how significant the security concerns are," says one UK source. "But ultimately the reality is that the port staff have been withdrawn and that reflects the broader political dynamic."
The fact that the Commission swiftly reversed course on Article 16 has not changed this new reality. "The EU obviously moved very quickly to correct things, but it has fundamentally changed the dynamic. We can't expect to go back to how it was before."
On Tuesday, Michael Gove told the Commons the UK could, indeed, trigger Article 16 itself. There was now an urgent need to address the upheaval the Protocol was visiting on businesses and consumers.
By Wednesday, Boris Johnson was telling the Commons: "We will do everything we need to do, whether legislatively or indeed by triggering Article 16 of the protocol, to ensure that there is no barrier down the Irish Sea."
This was raising alarm bells in Brussels. By its very nature, the treaty Johnson signed establishes trade barriers down the Irish Sea, and the agreement Gove signed in December was signed to limit those barriers as far as possible.
Within minutes of the Article 16 issue blowing up last Friday, Maros Šefčovič spoke by phone to Michael Gove, then to Micheál Martin and to Simon Coveney. "We wanted to diffuse the potential for political tension immediately," says a source close to the Commission vice-president.
Šefčovič spoke again to Gove on Saturday and proposed a video conference that would bring both men together with DUP leader Arlene Foster and Sinn Féin vice president Michelle O’Neill.
Šefčovič was keen to hold the video conference as soon as possible, even that weekend. Gove offered to arrange the meeting, and it was scheduled for Wednesday afternoon.
While Dublin viewed Downing Street’s initial reaction to the Article 16 affair as helpfully restrained, by the time the video conference got underway the Commission was suspecting that, rather than help put out the fire, London was deliberately keeping it going.
On Tuesday night, a decidedly needling letter from Gove landed in Šefčovič’s inbox. By the time Šefčovič had digested its contents, it had already been leaked to the BBC.
Gove did not spare the horses in lambasting the Commission for the events of the previous Friday. The reaction across the two islands had been "overwhelming… even more negative than I had anticipated. Across all political parties, civic society and business organisations in Northern Ireland, there was a sense of shock and anger."
The Commission’s actions had only "deepened anxiety" for citizens and businesses, who were already concerned "about their health and livelihoods at this very difficult time".
Even if the Commission had withdrawn the move, it did not alter the fact that it had "profoundly undermined the operation of the Protocol and cross-community confidence in it".
Gove set out six demands, solutions for which would have to be agreed by the Commission "this week".
They included extending until "at least 1 January, 2023" the grace period during which export health certificates (EHCs) would be waived for food products of animal origin, and the six month grace period in which sausages, mince and chilled meat dishes would be permitted should be extended to the same date.
If the EU didn’t agree, then the UK "will consider using all instruments at its disposal". Technical solutions were no longer enough. Such solutions, Gove suggested, were what caused the Commission’s error last Friday. Nor was the Good Friday Agreement built on "technical solutions".
EU officials were dumbfounded at what appeared to be an ultimatum, one reminiscent of the Internal Market Bill. Give us the concessions we want or we will trigger Article 16.
UK sources insist this is not their preference, and are reticent about what "all instruments" at their disposal means exactly.
Šefčovič is known to have a good relationship with Gove. However, he was stung by the notion that the EU had a cavalier attitude to Northern Ireland, or that it had somehow used the North for its own ends during the Withdrawal Agreement.
When the video conference got underway at 6pm on Wednesday, Gove was much less confrontational. Both sides had a "shared understanding" of the challenges and practical solutions were needed. He was "completely open-minded" on what these solutions should be.
There was no mention of the letter throughout the meeting.
Šefčovič apologised for what had happened last Friday, but reminded the meeting of the EU’s track record in supporting peace, "not just now but for decades, not only politically but financially," according to a written record of the meeting, seen by RTÉ News.
EU and Irish officials have stressed that the offending regulation of last Friday was about whether or not vaccines would be granted export authorisations before they left the factory, and not about putting a hard border on the island of Ireland.
Such authorisations would be required for vaccine doses leaving the EU for third countries, but not if they were going to another member state. Since Northern Ireland is treated like a member state, then batches going to Belfast would - under the Protocol - have availed of that waiver.
However, since the Protocol also guarantees unfettered access for goods going to GB, this was seen as a loophole. Indeed, the offending paragraph in the regulation (which was swiftly removed) only said that "movements of goods covered by this regulation between the [European] Union and Northern Ireland should be treated as exports".
Šefčovič strongly denied at the meeting there had been any question of customs checks for vaccines at the Irish border.
Arlene Foster replied that the Commission’s attempted use of Article 16 was "deliberate and provocative".
The DUP was opposed to the Protocol, she said. They had warned about it, it hadn’t worked, it was "a disaster" and it could not be merely tweaked. The voice of unionism was not being listened to.
Foster was entirely unmoved by Šefčovič’s efforts to highlight the EU’s record in promoting peace. At one point he referred to the Commission’s financial support for the Peace Bridge in Derry.
"He was trying to be conciliatory and sincere, but he just hit exactly the wrong buttons," says one source attending the video call. "Arlene said, you don’t understand unionism."
As the 45 minute meeting drew to a close, Gove once again emphasised how "tense" the situation was in Northern Ireland. Brandon Lewis, the Secretary of State, again made the link between the Commission’s gambit the previous Friday and the tension on the ground.
"Friction at the border could affect all communities," Lewis said, according to the written note. "There are tensions in civil society which shouldn't be underestimated, in the unionist community more than others."
Šefčovič concluded by saying that the flexibilities he had agreed with Gove in December were not being implemented.
Later, in an interview with RTÉ News, he said: "We have to look how the UK [has been] implementing all the possibilities which are there, to make sure that we are really reducing the disruptions to the minimum, as it was agreed when we negotiated the [December] deal."
Officials say such flexibilities included the trusted trader scheme, simplifications to export health certificates for food products, the replacement of exit summary declarations by data typically provided to ferry companies, and further derogations on the movement of medicines.
These were things the UK had demanded, yet when they were granted none had been fully realised and put into effect by the UK authorities, says one senior source.
The most serious failure, said officials, was that the EU had still been denied access to the UK customs IT system.
Šefčovič's view is that the Protocol, and the flexibilities agreed last December, have to be given time to work. If the system needs fixing, the EU-UK Joint Committee is the forum to do it.
As part of last December’s deal, the EU had agreed to a reduced presence of EU officials on the ground (including the absence of a permanent office in Belfast) but only in return for guarantees that member states could monitor, in real time, the flow of goods entering Northern Ireland from Great Britain via HMRC’s IT system.
"We do not have the entire data right now regarding the trusted trader scheme," says one senior official. "So we're waiting. It's part also of the non-access to the IT system because we don't have the aggregate overview on this."
This was not a case of an over-zealous European Commission, said a senior source. Member states had been contacting Šefčovič to find out how long EU officials were being kept from fulfilling their role at Northern Ireland ports under the Protocol due to the intimidation problem.
UK sources have acknowledged that EU access to HMRC’s IT system has not yet happened, but that this was down to technical problems which officials are working hard on. There was a need to differentiate GB and Northern Ireland data, some of which falls under data protection rules.
A senior Northern Ireland Executive source says that flexibilities are being used. "We're only able to do what we're doing at the moment because of the maximum use of those flexibilities," says the source.
"There are a lot of companies who are on the trusted trader list who do not require EHCs at the minute. Without that flexibility, life would be really much more difficult."
Given the tensions, the threats and ultimatums, can both sides find a way out of this sudden flare-up?
Šefčovič’s view is that the Protocol, and the flexibilities agreed last December, have to be given time to work. If the system needs fixing, the EU-UK Joint Committee is the forum to do it.
London’s view is that, no matter what was agreed in December, in general the overriding principle of the Protocol should be that the impact on ordinary people must be minimised. That principle should trump any dogmatic insistence on EU rules being applied to the letter.
The problem is that the grace periods agreed in December will run out soon. From 1 April, supermarkets will need EHCs for products of animal origin, and there is widespread concern that they are not ready.
UK sources say that the supermarkets’ own internal surveillance systems should be able to obviate the need for EHCs - an idea about which the European Commission has been, at best, lukewarm - and that the three month grace period should be extended to give retail chains time to develop these systems.
The immediate problem here is that the Commission only agreed to the grace periods on the condition that the UK apply the EU’s food safety, animal and plant health (SPS) rulebook for the three and six month durations, and that the UK issues a "unilateral declaration" to that effect.
In one unilateral declaration, published less than four weeks ago, the UK pledged to follow EU SPS rules and to ensure that the EHC exemptions would be limited to an agreed list of trusted supermarkets.
The UK pledge concludes: "The UK accepts this solution is not renewable." In other words, the UK promised less than four weeks ago not to seek an extension of the grace period.
The second grace period is for six months and it covers sausages, mince, chilled meat preparations, which are normally banned from entering the EU from third countries.
In a second unilateral declaration, the UK pledged that during the six months, such products would only be sold in Northern Ireland supermarkets, and with labels saying they "may not be sold outside Northern Ireland".
Although there was no promise not to seek a further extension, the UK pledged that the grace period "will be used by supermarkets in Northern Ireland to adjust," and that, again, the UK would remain "fully aligned" with the EU’s food safety rulebook.
The view in Brussels is that "adjusting" means Northern Irish supermarkets getting their sausages and chilled prepared meats from south of the border.
UK sources, by contrast, are now questioning whether banning GB sausages - as well as seed potatoes and certain horticultural products - should be happening at all, if the principle of the Protocol is to make life as trouble-free as possible for consumers and businesses.
The EU’s response is that life would be much more trouble-free for consumers and businesses if the UK had accepted the EU’s offer to align with its SPS rules, an offer the UK flatly refused because of its sovereignty demands.
The circular arguments of 2020 are back to haunt us. This time there is no deadline to focus people’s minds, and opponents of the Protocol are spraying graffiti at Northern ports, and, according to reports, noting vehicle registration numbers.
The PSNI have said there is no evidence of loyalist paramilitary involvement, and there have been intensifying contacts between Dublin, Belfast, London and Brussels to lower tensions.
"It’s like panic buying," says one Belfast source familiar close to discussions. "If you tell people there’s nothing to worry about and no need to panic buy, that’s the first thing they do."
Dublin was deeply angered by the Commission’s Article 16 gambit, and Irish officials are still trying to ascertain how it could have happened.
It’s understood there is now an agreement in place that any upcoming legislation that may have even the slightest bearing on the Protocol is first run through the cabinet of Mairead McGuinness, Ireland’s EU commissioner.
But there are concerns in Brussels and Dublin that both Boris Johnson and the DUP are manipulating a tense situation to undermine a Protocol, towards which the latter have always been implacably hostile, but which the former negotiated and signed.
Indeed, Denis McMahon, the permanent secretary of DAERA, the Northern Ireland department of agriculture, told the Assembly’s agriculture committee on Thursday that graffiti at Larne Port first appeared on 21 January, eight days before the Commission sought to trigger Article 16.
Meanwhile, the shifting dynamics around the EU’s vaccine strategy, and Commission president Ursula von der Leyen’s role, including the Article 16 affair, are going on in parallel.
Member states have more to worry about than whether or not Northern Ireland consumers should be eating GB sausages, and London may be banking on Protocol-fatigue to help it chip away at its provisions.
But capitals remain determined to know what enters their single market.
"I have no compassion for [Boris] Johnson, other than when it comes to the Commission’s Article 16 fiasco, which we would really like to get an explanation about," says Morten Helveg Petersen.
The Danish liberal MEP and member of the European Parliament’s UK Coordination Committee adds: "But he’s abusing the situation shamelessly and opportunistically. We shouldn’t fall for that."
Rather than Northern Ireland adapting to the Protocol, for all its challenges, the issue has again become intensely political and polarising.
The DUP, which has a five point plan to sink the Protocol altogether, believes the grounds for the UK triggering Article 16 are already ripe, and Michael Gove has surely hinted that he agrees.
The Irish peace process has weathered numerous breakdowns and surges in tension.
Since the Protocol must be tested for Assembly consent every four years, such surges and breakdowns are potentially built in, unless the political and the technical dynamics around Brexit and Ireland can find some kind of equilibrium.
Europe Editor Tony Connelly and Deputy Foreign Editor Colm Ó Mongáin look back at a hectic two weeks of blunders, blindsides and border bitterness in the latest episode of the Brexit Republic podcast.
Read Tommie Gorman tomorrow for the latest on the 'border down the Irish Sea' rumpus and why the stakes are so high for DUP leader, Arlene Foster.