Jeremy Corbyn and his team have not been seen to understand Scotland, or understand its distinct politics. The Scottish branch of the Labour party, despite making six gains at last year’s general election (up from one seat in 2015), finished third. It has shown no sign of recovery under Richard Leonard’s leadership, with the party regularly trailing the SNP and Tories in the polls.

Since that election, though, the Corbyn leadership have begun to recognise that Scotland matters if Labour is to win a general election. Of the seats that Labour needs to gain to form a majority government, 18 of its targets lie in Scotland and all of them need to be won from the SNP. And that is assuming it can hold on to what it gained last year, which is not at all clear.

Scottish Labour has not gained from the Corbyn surge. It has had no major inflow of new members, unlike in England and Wales. The people who would have joined a Corbyn-led Labour in Scotland had already joined the SNP, which expanded fivefold after the independence referendum.

If Labour wants to reconnect with the energy and activism of left-wing independence opinion, it needs to develop a different politics on the constitution and future of Scotland and the UK.

Here is the speech that Jeremy Corbyn should be giving:

I have always felt that Britain is rigged against the vast majority of working people. There has been no level playing field – despite the efforts of past Labour governments to reduce inequality and widen opportunity and life chances. I am coming to the realisation under my leadership that this calls for even more bold ideas and policies than I initially thought.

Scotland has much to teach us – and much to teach someone like myself who has spent a lifetime steeped in Labour.

So, I want to say thank you to the generations of Scottish radicals – pro-devolution, pro-home rule, which Keir Hardie so passionately believed in – and yes, pro-independence supporters. I understand and respect your desire for change across these isles.

The old story of the left is that a majority radical Labour government elected on a progressive programme and bold manifesto based on a popular mandate would be able to drive through far-reaching change. Yes, it would meet resistance from the usual places and suspects – the Lords, the City, the business lobbies; all of them threatening their worst. But the right programme could fundamentally change this country.

But this story still treats politics as something done to too many people, because some of us know better. I have supported that view of politics –and I have to tell you that I now see the error of my ways.

There are several reasons we need to go much further in our radicalism. We are living in the age of Broken Britain. I know, and you know, that the social compact that weaved together citizens, institutions and government has been trashed by those with money, power and status.

This means that the old ways are no longer enough. Let me put it in plain words. You cannot build socialism on top of the Empire State. This is an unreformed, undemocratic state – a voice and apologist for the real closed shops and vested interests which have governed Britain looking after only themselves.

Here I want to turn to Scotland and the ongoing Scottish debate, which I have not paid enough attention to. Many of you understood the broken nature of Britain much earlier than the Westminster bubble. And drew from it the conclusion that Scottish independence was the only way to address this.

Britain is broken. The old unionism of Tories and Labour is bust. And our party made a critical mistake in the referendum. One as serious as campaigning on the same platform as the Tories.

We made the wrong case for Britain. Labour’s founding fathers – Keir Hardie, James Maxton and Tom Johnson – made the case for the union as a means to an end. That end was social justice, workers’ rights, an end to injustice and exploitation. The union made us strong – as the banners say.

But in the referendum, this was an impossible case to make. We slipped without realising it into making the case for the union as an end in itself. That is the Tory unionist unconditional argument for the union. And no case for a radical, democratic, egalitarian party like ours. So from this day forth we will not make that argument for the union again.

I want to venture from this into the unthinkable. We need a new British compact. Your referendum has shown us this. As has Brexit. But this storm has been a long time brewing.

The entire edifice that is the UK is shaking to its very foundations. Scotland and Northern Ireland, pro-European, are not respected in this union. England is in an unhappy place. And Wales is being dragged along reluctant and unsure. We cannot continue as if none of this has happened and behave as though somehow conventional politics will save us.

Old-style Conservatism does not work. But let me tell you – neither does old-style Labour. And it isn’t enough to talk of UK-wide constitutional conventions or even vague notions of federalism which never amount to anything more than mood music.

We need a new idea of what Britain is. Humbler, more democratic, shorn of the arrogance and sense of superiority that has characterised both Conservative and Labour governments.

So I want to say something unusual for a British Labour leader: I am relaxed about Scottish independence. I understand the case for Irish unification. And I choose my words carefully – in what are debates with deeply held views – I am comfortable if Scottish Labour members are for, as well as against, independence. We have to be open if we are to debate the existential questions that ran through your independence debate. What kind of society do you want to live in, and what kind of state and set of arrangements best aid that?

We know it isn’t the status quo. We know the constitutional status quo and elective dictatorship that is the British government has been used to engage in a massive transfer of income, wealth and assets, to a tiny, self-aggrandising elite – who present their version of the world as the only way.

We need looser, freer, more modern kind of arrangements across the UK and these isles. We need to move from a marriage where divorce is complex and messy to one that is based on consent and respect – we could even call it co-habitation.

This would not be a vague federalism. But it could be something that was uniquely British – made by the best of radicals in these four nations. It could even be one where not only the idea of Britain changes, but Britishness as well.

For this to be more than warm words, we need to think big. Look at the state of our politics, the world, why Brexit happened. Britain is on the move and we need to remake everything about it including the political centre.

So today I am announcing a Labour initiative on the future of the UK. I am inviting people from across the political spectrum who are committed reformers: from my party, Lib Dems, Greens, SNP, Plaid Cymru, and even the odd Tory, to serve on it.

Its remit will be to find a set of structures post-Brexit that ends the Broken Britain and the rotten No Room at the Top politics. It will be an UnRoyal Commission on the Constitution – 50 years after Harold Wilson announced the first Royal Commission on the subject – and it will have a remit to go beyond federalism and consider every possible option, including confederalism. And I am mandating it to come back with its first report – its initial recommendations – one year from today. Time is of the essence.

I realise the magnitude of what I am proposing. I know I have been slower than I should have been in getting to this point. After three years as Labour leader, I realise more than ever how our politics, our country and the very fabric of society needs really radical solutions.

Traditional politics hasn't looked after the interests of the people. And we have to change course. That has to be about more than just saying “vote Labour, we are different’”. We are – but we must prove this everyday in thousands of ways.

It is time to challenge conservatives across this land who say this is the best we can do: in how we are governed, do things and interact with each other. It is time to respect and trust people and give them the tools to make the big decisions.

You started this process here in Scotland – and I salute you. Let’s now carry that democratic spirit out across this land – and start what will be a democratic revolution. The days of the old Britain are over, and Labour will work with anyone who is prepared to bring it to an end and create a new settlement which works for the many, not the few.