A hard Brexit could push Scottish independence “over the line,” Tony Blair has suggested as he called for a greater UK identity, mentioning the idea of merging England and Scotland’s football leagues.

In an interview with the Institute for Government think-tank to mark the 20th anniversary of Scottish devolution, the former Labour Prime Minister, whose government instigated the major constitutional reform in 1999, suggested Nicola Sturgeon’s SNP misunderstood the concept of nationhood.

“Scotland as an independent country would immediately lose its ability to influence things through membership of the UK,” declared the former PM.

“I always say that the arguments of the Brexiteers are very similar to the arguments of the Scottish Nationalists ultimately. It’s just a misunderstanding of what nationhood really entails in the 21st century.”

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Mr Blair told the IoG that people in the UK should think more carefully about how they had a British and UK identity and not just an English, Scottish, Irish and Welsh one.

“That’s important. People used to think it was a bit trivial when I used to say we should put the football leagues together…It’s just you need to find ways in which people are realising they have a lot in common, as well as space for the diversity of the UK. I’d do a lot more of that.”

He explained how once devolution occurred, even institutions like the BBC “became separated in a very clear way. You just lost that sense of a common agenda that you are waking up to every day. Obviously, that’s now happened…We need to be more active and passionate in our defence of the Union. And maybe if one good thing comes out, once we get rid of this Brexit thing, is that we really need to think about what is the place of the UK in the world and why is it sensible for countries to be together in the UK”.

Reflecting on the two decades since the first elections to a “reconvened” Scottish Parliament, the former PM said it was important for Labour to have succeeded particularly in Scotland, where the support for independence would have been "unstoppable” without devolution.

He said the issue of Scotland’s future was a continuing debate but noted: “We’re still the UK and we’re still together so you’ve got to put a tick there. Are there still pressures for secession? Well, in Scotland, yes, but I still think they won’t succeed unless Brexit pushes us into a position where that kind of gets Scottish independence over the line; if you have[a] hard Brexit, which is possible.

“And in Northern Ireland, without Brexit I would be very confident that the Union would stick together but again Brexit is an issue there.”

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It was suggested to Mr Blair that if Brexit happened, it would be very hard to resist demands for a second Scottish independence referendum because the facts would have changed.

He replied: “Yes, the facts will have changed. I still think we should be very careful doing it[indyref2] unless it’s clear that there’s a huge groundswell for it. You know, one of things that Brexit has taught us is the danger of playing around with referendums in our country. These are big decisions which alter the whole nature of the country.”

And yet the former PM decried David Cameron for not proposing a confirmatory vote on any Brexit deal against the status quo.

“It’s obviously sensible that once you negotiate a settlement you say: ‘Tell us: do you prefer the house you’re in or the house you are moving to?’ That’s reasonable.”

In the interview, Mr Blair referred to the “Brexit imbroglio” and decried what he described as English Nationalism within and outwith Westminster.

“What’s weird at the moment is you’ve got Conservative MPs like the Boris Johnsons, the Rees-Moggs, who say they’re vigorous Unionists but are actually really playing on English Nationalism,” he explained.

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“I’m quite shocked by the amount of people who are Brexiteers in England who, when you put to them that it could cause a strain on the Union, just kind of shrug their shoulders and say: ‘Well, we don’t care.’ I mean, it’s just really shocking, actually. Because that’s just profoundly ignorant of our history, what’s brought us to here and the way the world is changing outside the UK.”

In the years following devolution, Mr Blair suggested: “The most interesting development in Scotland has been the decline of the Labour Party and the resurgence of the Conservative Party. Now, that has been very simply because the Conservatives have spotted a gap in the market that Labour have left; pro-Union, pro-reform.”

The former PM added: “By the way, 20 years is not long in a new constitutional settlement. I don’t think we can judge devolution properly…probably for many decades.”