The Irish protocol.

Yes. In fact NI-RoI trade is booming, and there is some suspicion that part of the reason may be GB-RoI trade being routed through NI to avoid checks and controls. (Direct GB-RoI trade has fallen significantly.) But, two things about this:

1. We don't know this for sure; it's just a suspicion. While we have good data on NI's trade with RoI (and the rest of the EU) we have very poor data on NI's trade with GB, because the UK doesn't compile or collect that data. (Which, incidentally, will be a problem for them if they want to invoke Art 16 on the basis that there has been "diversion of trade" between GB and NI).
2. It's not necessarily the case that people are routing goods from GB to RoI via NI in order to import goods that are non-compliant or that would be turned away at Dublin port or whatever; what they are doing may not be in any sense cheating, or improper. They may simply find that it's quicker or cheaper or both to import via NI because the relatively light checks operated GB-NI are less onerous or less time-consuming than the fuller checks operated at Dublin Port. This would be the flip side of RoI (and indeed NI) exporters avoiding the landbridge route to the mainland and exporting by direct sea routes instead; a natural and expected response to the burdens imposed by Brexit.

Can't get behind the paywall but this commentator is throwing a bit of fuel on the fire, groan.

https://www.belfasttelegraph.co.uk/business/northern-ireland/reunification-of-ireland-is-close-says-top-economist-posen-40920667.html

The lack of clarity that people complain about is, what exactly is meant by "diversion of trade"? There's no definition or explanation in the document itself.

A literalist interpretation would say that, if any trade transaction is altered in any way in response to the NI Protocol, the condition is satisfied, but that would absurd, and in interpreting legal documents (and this is a legal document) the courts generally rule out absurd interpretations as, well, absurd. The principle here is that you're looking for the joint intention of the parties, and it's wildly unlikely that something so absurd is what the parties jointly intended.

Similarly, for the reasons already pointed out, it would be absurd to suggest that if the protocol leads to an increase in EU-UK trade, that would in itself be a "diversion of trade" that justifies disapplication of parts of the protocol. So that's definitely not what it means.

So, what does "diversion of trade" mean in this context? What is a non-absurd understanding that the parties might be taken to have jointly intended?

There are a couple of considerations that I have seen raised in academic/professional writing about the Protocol. I offer them for what they're worth:

One point that is often made is that the Protocol is part of an international treaty between the UK and the EU, so the default meaning of "trade" is "trade between the parties" - UK-EU trade. Internal UK trade is in general no concern of the EU's, and internal EU trade is in general no concern of the UK's; if the treaty was going to concern itself with either of those things it would have to do so in very clear, explicit terms. So, if "diversion of trade" was intended to refer to trade between NI and GB, the treaty would say so. This argument is said to be reinforced by the fact that, when the "diversion of trade" language first appeared in the draft text, the draft treaty was still contemplating an all-UK backstop, so there was no reason to suppose that either party was thinking that it might distort internal UK trade. The concern being addressed was something like this: GB exporters to the EU may divert trade from the Channel ports and route it through NI instead in order to avoid the full rigour of EU checks and controls, which is not what the NIP is supposed to be about. That would be a diversion of UK-EU trade that would entitle a party (ironically, the EU) to invoke Art 16.

The counter to this argument is that, as the whole point of the protocol is to treat NI differently from GB , and so it was always at risk of distorting NI-GB trade. So, whatever the parties were thinking of when the language was first introduced, by the time the agreement was finalised they must have been thinking of the possibility of NI-GB trade being affected.

The counter to that argument is, duh, the treaty provides for checks and controls on trade moving from GB into NI. Of course that's going to affect trade flows; that's the whole point of checks and controls. It's absurd to suggest that the NI Protocol operating as both parties intended an in accordance with its plain terms is a reason for suspending the application of those terms. If that was what the parties intended they would have just not included those terms in the first place. The parties must have been thinking of trade diversions which are not the obvious and natural consequence of a plain reading of the terms of the Protocol.

A separate line of argument suggests that, to understand what "diversion of trade" means we should note that it is bracketed with "serious economic, societal or environmental difficulties that are liable to persist". It's obviously something different from those difficulties, or it wouldn't warrant separate mention, but comparable with them in significance, or it wouldn't be grounds for invoking Art 16. So, this argument runs, you don't look so much at whether the trade being diverted is NI-GB trade or NI-RoI trade or wider UK-EU trade or whatever, but more at the nature and scale of the diversion. And then you ask yourself if a diversion of that nature and scale is likely to have consequences that are comparable to the consequences that serious and persistent economic, etc, difficulties would have.

We can illustrate this argument by considering its application to the iconic sausage problem that received so much attention in the Brexity press in the UK some months back. Let's assume that the checks and controls on chilled meats would make it impractical to import mixed containers into NI that include chilled meats so, if you're going to send in sausages, it has to be a container of nothing but sausages. But NI is, if not quite a global sausage powerhouse, certainly a large producer of sausage. It produces far more sausage than it consumes, and it exports the surplus. So imports are really only of specialty sausages, or imports for the likes of M&S who insist on selling the flabby English sausage rather that the unquestionably superior Ulster product. But, precisely because these are fairly niche markets, the volume of sausage imported is small, so entire containerloads do not come in. So the end result is little or no GB sausage in NI. Is this "diversion of trade" that would justify invoking the NI Protocol?

No, is the answer, because it does not result an any material sausage shortage. The people of NI can eat all the sausage they want and, if we're honest, probably more than is good for them. The boreens and market squares of Ulster will not exactly be littered with the whitening bones of those who died for want of sausage. If anybody's adversely impacted here, it might actually be sausage producers in GB, who are effectively excluded from the NI market. But (a) it was a small market for them anyway, plus (b) we know what Brexit in general is doing to them; when they can no longer produce sausage in the quantities they used to and pigs have to be culled, the loss of the NI market is irrelevant; they still have a bigger market than they are capable of serving. Any diversion of trade resulting from the NI Protocol is wholly eclipsed by the much larger diversion of trade resulting from GB's hard brexit.

None of this is to say that there might not be other diversions of trade due to the NI protocol that would have more significant consquences than the sausage problem does. But it highlights that, to make a case for applying the protocol, we have to identify the trade that is being diverted, quantify the diversion and demonstrate that is has a significance that can meaningfully be compared to "serious economic, societal or environmental difficulties that are liable to persist".

All that was bothering Jim Allister was the Irish language act last night on Nolan Live, must be killing him that his beloved Tories were pushing through the act over their heads.

We have been telling you this for nearly a year now. The EU will facilitate flexibilities and easements built into the Protocol but will not re-negotiate the Protocol itself.

The reason 'we are here' is because the UK has not fully implemented the Protocol yet and sat down to implement the flexibility and easements.

Unionist protests are a colourful, if pathetic and self harming, sideshow.

There will always be a sizable chunk of people in NI who will prioritise unhindered trade between NI and Britain because they see it as part and parcel of their nationhood, but everyone else, be it Irish nationalists or just people who prioritise economic stability over identity, have to be looking at what's going on in mainland UK and be thinking the protocol isn't a bad state of affairs at all.

The problem with Brexit is that it's a total folly the way Brexiteers have been conducting it. First they said it would be all upside. They said it would be an easy deal and the UK would continue to enjoy access to the SM. Now they're saying that it's going to be hard, but there are opportunities down the line. That may be, but a concussive economic impact is not what many voting for Brexit signed up for, and if the people of NI can avoid the worst of that by having actual continuing access to the SM, it's a better state of affairs from what their counterparts in the rest of the UK are now beginning to really feel the effects of. Maybe NI can vote to drop the protocol if/when that land of milk and honey has been delivered and dropping ties to the EU makes more sense, but until then....