THE end of the Union is coming fast – and the SNP "are not going anywhere" amid Labour's Unionist mindset, according to MP Clive Lewis.

The Labour politician pointed to Brexit as putting "rocket boosters" under the breakup of Britain.

Lewis was speaking on the Oh God, What Now? podcast, formerly known as the anti-Brexit Remainiacs podcast, following Labour's Brighton conference.

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He said: “When you think about the uphill struggle we’re facing now with the breakup of Britain, the breakup of Britain is happening, whether we like it or not.

"The raison d’etre for the United Kingdom was an imperial project, you know, you needed to have that critical mass, in landmass, resources, people power, to run the empire, to win the empire.

“The empire physically now has gone, and Brexit – if you want, I’m sure it’s been described in your show before as a kind of post-imperial tantrum of this country – and that has, not by design, but the outcome of that, with Scotland voting to stay inside the European Union, has seen the breakup of Britain, I think, been put on rocket boosters.

“The SNP are not going anywhere. What they’re offering the people of Scotland is something that Labour will never be able to replicate whilst it has this kind of Unionist, first-past-the-post mindset.”

Lewis attracted the ire of centrists within his party over a column in The National last year.

READ MORE: Clive Lewis: Scotland has the right to decide its own future

The then leadership hopeful looked to tackle the party's dismal performance north of the Border by calling for Scottish Labour to be fully independent and backed a second independence referendum.

In his column, he wrote: "In the words of the 1989 Scottish Constitutional Convention, supported by Labour MPs, I believe 'in the sovereign right of the Scottish people to determine the form of government best suited to their needs.' 

"It is not for me, as an English MP for an English constituency, to dictate to Scotland what that form of government should be, and there should be no question of Labour opposing a second independence referendum if there is a mandate to hold one.

"It remains my conviction, nonetheless, that radical federalism, with the maximum possible autonomy for Scotland would provide the best solution for all the constituent nations of the United Kingdom.

"This is because my politics is driven by a belief in building alliances and whether in the UK or in Europe, I believe we are stronger when we work together. But I want to be part of a union where everyone feels heard and their needs are accounted for. We have to be honest and admit that this simply isn’t the case at the moment."

Earlier this year, he said: "Post-Brexit it now seems increasingly clear the Scottish people have two clear choices before them: 1. Union with a declining imperial power, ruled by hard-right, neoliberal English nationalists – or ... vote for Scottish independence and look to rejoin the EU, an emerging power with democratic institutions gaining in power, not receding. Hmmmm."