This is the Union's fatal failure in the Brexit process

It remains legally in the UK customs territory, while practically remaining in the EU customs union. There are no border checks proposed on the UK-Irish border, but instead new checks between the province and the mainland.

The deal puts forward the “consent” principle whereby the Stormont Assembly – currently suspended – can vote by simple majority every four years to continue these arrangements; if there is cross-community consent this can be extended to eight years.

This is a shift from the first Boris Johnson package which proposed that “consent” needed cross-community approval by both Unionists and nationalists, and hence gave the DUP a veto. With the Unionist parties having lost their majority for the first time in the last Assembly elections in 2017, the DUP are furious and feel “betrayed” by Johnson. But it also because they can read future trends and know they are going to become an embattled minority in the province.

READ MORE: £3.3m Skye Bridge tolls imposed unlawfully says Robbie the Pict

The new package and Northern Ireland arrangements have been defended by most Tories and right-wing opinion. Fraser Nelson, editor of The Spectator, commented: “This Boris deal gives companies a strong incentive to relocate to Northern Ireland. They’d benefit from frictionless EU access and future UK trade deals’, concluding that this ‘makes for a richer Ulster, ergo, a stronger Union.”

Leave aside the sloppiness of using Ulster as synonymous with Northern Ireland, or in the piece suggesting the province was separate from the UK, First Minister Nicola Sturgeon responded to Fraser’s analysis: “Scotland’s competitive disadvantage from ‘the deal’ in a nutshell, ergo, I’d suggest it’s not good for the Union at all.”

Why has the UK got itself in such a mess? This after all is the country that likes to profess its continued adaptiveness and pragmatism. The UK, as we all heard ad nauseam in the indyref, is a political union of four distinct nations rhapsodically defended by the Tories as the “precious Union” and even less impressively by Boris Johnson as “the awesome foursome”.

The UK is historically and in its composition a union state with differentiated arrangements across the four nations. Scotland and Wales have devolved Parliaments and for Northern Ireland the hope of its Assembly being re-established in the near-future.

The story of this Union used to be one of the main clarion calls of Unionism. A politically sensitive Unionism today would have recognised the realities of Scotland and Northern Ireland voting to remain in the EU, and advanced a differentiated Brexit across the four nations to accommodate these divergent demands and needs. Northern Ireland has ended up with unique arrangements primarily because it shares a land border with the Republic and hence has become the UK’s land border with the EU. This became acute after Theresa May threw away her majority in the 2017 election and needed the votes of the DUP to remain in government with a majority.

But that is only the recent story and something much more significant is at play which is relevant to Scotland’s situation. This is the near-complete lack of political insight, intelligence and nuance left in the UK Tory Government and forces of Unionism about how they understand the nature of the Union of the UK.

It seems a different political universe, but in the age of Harold Macmillan and Winston Churchill, British Unionism had a powerful and popular story to tell about the UK and its Union. Tory Unionism in particular had a grasp of the patchwork, localist and adaptive nature of the Union. In part this was as a stand against the growth of the central state under Labour, but was also a historic championing of local communities (and of course, their own particular elites and business interests).

There was even a Labour version of Unionism – one which emphasised the good story of Britain as a progressive vehicle for change domestically and globally. It stressed the creation of the NHS and welfare state, the forward march of worker rights, and internationalism such as the Commonwealth.

These Tory and Labour accounts of Britain are threadbare to close to completely dead today, with people such as the former Tory Rory Stewart one of the last Tories who embodies this past Britain. Gordon Brown is the last living exponent of that once powerful strand of Labour and does not recognise that he is invoking a passing world, rather than the present and future.

Rory Stewart

THIS version of Britain – if it were alive and kicking today – would have advocated a Brexit which understood Scottish as well as Northern Irish sensitivities. Senior Scottish Tories of the old patrician school would have told Downing Street that they needed to respect Scotland’s status as a nation and democracy. And this would have been understood by the collective muscle memory of Unionism.

READ MORE: Great-great gran and six-week-old meet Nicola Sturgeon

Instead, the 13 Scottish Tory MPs have zigzagged – being prepared to support a No-Deal Brexit and now this week desperately clinging on to the wreckage of Boris Johnson’s deal. It isn’t a good look or place for any kind of defence of the union – principled or pragmatic.

This is an existential crisis of unionism in the here and now which is going to grow more acute in the future. The revised Withdrawal Agreement has 111 mentions of Northern Ireland, 21 to Ireland and five to the island of Ireland, and zero for Scotland. When this has been pointed out to Tories and unionists they poured scorn on this and cited the special status of Northern Ireland.

But in so doing they have underlined the moral and political hollowing out of unionism – which would have once grasped the need to find special provisions for Scotland. Blair McDougall, former head of Better Together, responded to the above figures: “Why isn’t Scotland mentioned in the Mersey Tunnell’s [sic] Act either eh?”

Brexit came from a particular set of English anxieties and concerns which became wrapped up in the reactionary voices of English nationalism, a perspective increasingly uneasy with much of the modern world and even modern England and hankers after a world when times were simpler.

The past three years of charge and counter-charge have only increased the indignation and anger which part of English nationalism feels both for the rest of the UK, and indeed for much of England. As time has passed since the 2016 vote the intensity of frustration and feeling disrespected by the political classes has only grown, and may evolve in the future into something even more ugly.

Brexit was built on the foundation of an already increasingly disunited kingdom and has magnified still further the divisions and fissures in this political Union. But one of the biggest drivers in all of this, in the past three years and over the past couple of decades, has been the decline of a unionism that understands the UK and the political power centre of the UK – increasingly failing to grasp the needs of people who live outside its orbit and do not share its worldview.

In this – for all the rightful complaints the Scots and Welsh have – the North of England, with little political lobbying power in Westminster and Whitehall, has been virtually ignored for decades, which has been a major contribution to Brexit.

In trying to reach a deal Boris Johnson has conceded Northern Ireland a special place while denying Scotland any similar recognition, and in so doing has run roughshod over the fundamental nature of the Union he claims to champion.

READ MORE: Brexit is a triumph of the populist right-wing of Britain

When the history books of the breakup of the UK as we know it are written, Brexit will get its own chapter and Boris Johnson’s deal its own section. Nicola Sturgeon said on the eve of Westminster’s debate yesterday: ‘‘History will look back on the day this deal passes as the day the Westminster political Union died. It will have been demonstrated to Scotland, because Northern Ireland will have been set on a particular path, that our voice can’t be heard within that Union.’’

This may not yet be the beginning of the end of Brexit, but we are in the advance stages of the beginning of the end of the United Kingdom as we have known it.