On March 29, 1673, the-then English Parliament introduced the Test Act, penalising Catholics and non-conformists alike.
The impact of the Act was far-reaching and led to deep divisions in society. The Act was not repealed for more than 150 years.
The greatest impact was felt in Scotland and Ireland. This morning, another parliament dominated with English interests will start the process of something that will be equally devastating for societal cohesion as the Test Act and its political fallout may last just as long, too.
The long-anticipated triggering of Article 50 by the Tory Prime Minister Theresa May to leave the European Union sets a course for the future of the United Kingdom which will be irreversible. Mrs May's almost Damascene conversion to the cause of Brexit seems to befit her clerical upbringing. The cause of Brexit long campaigned for by ideological zealots, romantic imperialists and little Englanders is about to come into being as the British Government plan - if that's what you could call it - for negotiations looks as if it came directly from the handbook of a Kamikaze pilot.
Belatedly, the British Labour Party appears to have awoken from its self-induced coma, but frankly its efforts are a case of too little, too late.
Its six tests so ably argued by Sir Keir Starmer, which he claims must be passed before supporting any eventual Brexit, are the very arguments Labour should have been making more forcibly during the referendum campaign. Lukewarm doesn't even come close to describing the Corbyn/McDonnell junta approach to the debate. If British workers, women and disabled lose hard-won rights following Brexit, then the Labour leadership are equally culpable as bungling Boris.
Mr Corbyn shares complete responsibility for the calamitous nature of the Brexit process along with Mrs May's Government. His lacklustre and ambivalent approach to the referendum and his subsequent lamentable leadership of the Opposition has meant that even the trio of Brexit stooges in the shape of Johnson, Davis and Fox are able to escape scrutiny with considerable ease.
For all the commentary and British bulldog rhetoric, Brexit is not about the shared interests of the United Kingdom.
It is, as it always has been, about the narrow interests of a small group of wealthy individuals and select media outlets that piggy-backed and exploited legitimate concerns about immigration and turned the referendum into something it was never intended to be about.
Instead of facing up to the failed domestic policies of a Conservative Government that has left the UK hopelessly divided, politically, socially, ethnically and economically, they turned the EU and immigrants into bogeymen. The nonsense about membership of the EU being driven by elitist liberals was nonsense, as the Electoral Commission funding reports show that the Leave campaign out-spent the Remain side.
Naturally, some unionists flocked to the Leave banner like lemmings on a cliff-top. One went as far as to say it didn't matter what the cost of leaving the EU was as long as we left. That's some statement, because it meant no matter what the cost to farmers, to food producers, to manufacturers, for job-creation, or for the voluntary sector, better to crash and burn in the forlorn hope that it somehow perversely made the place more British.
Interests that are not our interests are now pushing the Brexit policy triggered by this particular British Government.
The Tories have one solitary MP in Scotland and a derisory less than 1% of the vote here in Northern Ireland. Theresa May now tries to cover up the divisions within the United Kingdom using regional photocalls as a fig leaf for meaningful engagement. Of course, our position in any forthcoming Brexit negotiations is substantially weakened by the failure of Sinn Fein and the DUP to create an Executive earlier this week and matters are compounded by the fact that this British Government has little to no empathy for Northern Ireland on its front benches. This is a government suckled on a bygone British way of life informed by Enid Blyton, Bertie Wooster, Enoch Powell and Brideshead Revisited.
The strong regional characters that once played leading roles in their respective Cabinets rooted previous Labour and, indeed, Tory governments with an understanding of what makes the United Kingdom tick and, indeed, stick.
Where are today's big political beasts on either front bench, like John Reid, Roy Hattersley and John Prescott, or Chris Patten, Michael Portillo, Ken Clarke and Michael Heseltine?
Here in Northern Ireland, we are more isolated than ever before. Thanks to English interests, we have been set on a journey without a map. Only the remnants of the Good Friday Agreement may yet save us, as the EU bought heavily into our peace settlement.
The EU pumps hundreds of millions into the border regions and that funding is not so easily replaced. Already, the agri-food sector is beginning to realise that and the so-called "shared interests" of the UK are in meltdown as the regions, like various industrial sectors, slowly discover that the Tory elite interest is even more "Me Fein" than Sinn Fein's agenda.
The Irish government has a unique role to play going forward in that - they and not the British will know the willingness of the other EU countries to regard Northern Ireland's status as somewhat unique. Remember: our troubles reached Germany, Holland and Spain, so EU politicians will not forget that easily.
As for the border - despite the wishful thinking and contorted explanations from British ministers that it can be business as usual, the border is coming back and it's just a matter of where and how.
Instinctively, common sense would say it would be incompetent to have physical structures re-established at Newry, Derry and Strabane, but it's hard to see how one is avoided.
More likely is the prospect that borders will be around Ireland than within Ireland as those carry less political risk - though unionists carrying their passports to travel within the UK may have some indigestion.
To those that say Brexit is Brexit, so just get on with it - or, in the case of the local Tories, with their mandate of a mere 0.4% of the Northern Ireland electorate, whose representative said, "Just suck it up" - I say quite bluntly: devolution meant gaining control of one's own affairs, particularly those that impact greatest on everyday life; we won't give up on that so easily.
To now expect the people of Northern Ireland to reject their democratically arrived at decision to remain in the European Union and to surrender or subsume it for the benefit of some kind of heroic self-defeating exercise like the Charge of the Light Brigade, on behalf of a section of society that does not share our best interests, is very typical of John Bull-type bombast.
The EU, too, is going to have to show some creativity when it comes to Northern Ireland and it's not as if they don't have bespoke agreements and side-deals across the EU.
The European ideal was originally conceived on a notion based on securing lasting peace between former warring European countries and it would be a betrayal of its founders' idealism if current EU leaders sacrificed the resolution of one of Europe's oldest conflicts - that of England and Ireland - for some kind of political revenge for Brexit.
Economically speaking, there is no good Brexit deal for Ireland - north or south - that delivers in the terms that the Tory Government is now pursuing.
Politically speaking, our current domestic impasse is as much to do with estrangement over Brexit as anything else.
So, it looks like it's going to be a politically hot summer, followed by a very prolonged period of cold interludes.
- Dr Tom Kelly is chair of the Stronger In Europe campaign in Northern Ireland