WE all know them: the type that follow fashion, but only when it’s a bit too late. The type that turn up their jeans when everyone else is rolling theirs down, or grow a hipster beard when everyone else is shaving theirs off, or get themselves an iPhone 4 just as everyone is moving on to a 10. They’re called late adopters or fashion laggards and they were on my mind the other day when I heard that Jon Trickett, the Shadow Cabinet office minister, would be delivering a speech proposing a federal Britain. Talk about a late adopter. Where have you been Mr Trickett? Welcome to the party. Better late than never, sir.

As usual, the significant details of what precisely Mr Trickett means by federalism are missing, but the general mood of what he says, the atmosphere, seems to be along the right lines. He says that a radical shake-up of the British constitution is needed and that a federal structure could be stronger and fairer for every part of the UK, and popular as an alternative to independence. Mr Trickett also comes at the problems, and the solutions, from a distinctly Corbynite perspective – the British state in its current shape has not delivered a socially just country, he says. A federal Britain just might.

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Now, I may not agree with Mr Trickett that a Corbynite Britain is a destination we should be heading for, but I do agree – as most mainstream liberals and conservatives have for a very long time – that federalism is the only logical answer to our Rubik’s Cube of a constitution. In the words of my predecessor in this column, David Torrance, the United Kingdom is a weird country. So, isn’t it time Unionists did something to un-weird it and bring the constitution into line with other modern states – something profound, progressive and permanent?

Sadly, in the case of Mr Trickett’s proposal, we’re going to have to wait (and wait, and wait?) for the results of a constitutional convention, but the reasons for the shadow minister's conversion to federalism are highly significant. Apparently, he saw the light when he witnessed Conservatives suggesting during the 2015 General Election that Scots MPs could prop up an Ed Miliband government in the event of a hung parliament. Mr Trickett, it would seem, suddenly saw where the imbalances and quirks of our current constitutional state can lead: anti-Scottish sentiment from the Tories on the one hand, and pro-Scottish independence sentiment on the other. Answer? Fix the imbalances.

If you were looking for labels, you might call this the pragmatic, rather than principled, approach to federalism and it has pretty much got us where we are today. Unionists have been faced with a problem – nationalism – and have been pragmatically inching their way through devolution and quasi-federalism as a way of trying to damp it down. In response, the Scottish nationalists have belittled and criticised every advance, then accepted it, then purported to be its defender, and then sought to exploit it for their own ends. But the Unionist pragmatism has at least achieved one thing: it has brought us a little closer to a federal solution.

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I saw a little of this pragmatic approach myself recently from the former Tory minister Sir Malcolm Rifkind. Sir Malcolm has supported a federal UK since his days as a member of a group of young progressive Conservatives called the Thistle Group; he also resigned from the opposition front bench when Margaret Thatcher insisted her MPs vote against a Scottish Assembly. I spoke to Sir Malcolm about this in the middle of the Conservative Cotswolds. Sometimes, you can find rebels in the strangest places.

The point is that Sir Malcolm has always supported federalism for two reasons: first, because it is the fairest and most progressive solution for a country like the UK, but Sir Malcolm is a pragmatist too. He told me that he didn’t do more to promote devolution in the 1980s because there was no great clamour for it. Equally, the former cabinet minister now thinks federalism could answer the clamour for independence and convince Scots to stay in the UK. Pragmatism begets a possible solution.

I think there’s a great deal of sense in this, but it will only work if it’s the right kind of federalism and even then there are risks. In fact, there are two factors that should worry Unionists, the first being that the wrong kind of federalism will make things worse and potentially destabilise Britain further. Could you imagine a federal UK, for example, that gave an equal voice to nations that are far from equal in size? Great for Scotland, but what would the English make of it?

A much better solution would be a form of federalism that involved devolution within England. The traditional response to this from sceptics – and arch nationalists like the Scottish Green leader Patrick Harvie who seem suspiciously resistant to greater devolution – is that there is no demand for it in England. But what a weird argument that is. Has there always been a great demand for reforms that have made the country better? Don’t politicians have to lead the way sometimes?

My feeling is that the English could learn to love the idea. But even an even-handed, progressive form of federalism for the UK would not be the end of the story. Far from it.

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Federalism could – as socialists like Jon Trickett and Tories like Malcolm Rifkind hope – iron out the quirks in our weird constitution and convince Scots to stay in the UK. But, sadly, if the Brexit vote proved anything, it’s that being a member of a federal structure can actually fire up nationalism rather than dampen it down.

In fact, it’s easy to imagine the Brexiteer activists who railed against the EU doing exactly the same against a UK federal government. I can hear the anti-EU slogans now, repeated and reused against a federal UK: “take back our laws to England”. Which raises an interesting question: should those who care about the Union be worrying not about the fractious Scots, but the resurgent English?