If modern Britain has a defining problem, it boils down to an across-the-board failure to leave the past behind. Brexit, self-evidently, is a profoundly retrogressive project, helmed by Tory politicians split between continuity Thatcherites and devotees of a supposed one-nation Conservatism who still yearn for a quiet, sepia-tinted England. The latter are personified, in her own shaky way, by the prime minister. Labour, meanwhile, has a clear set of moral responses to an obvious social crisis, and the first stirrings of a convincing programme for government. But it, too, has a tendency to take refuge in fuzzy dreams of yesteryear: 1945, old flags and banners, the idea that a dependable job in a factory is still a byword for emancipation.

And all the time, the future takes shape. Academics at Oxford University’s Martin School say that as automation gains pace, even work in retail – which is all many places currently have left – “is likely to vanish, as it has done in manufacturing, mining and agriculture”. The era of driverless transport will soon be here. Even for the labour market’s winners, a digitised economy’s quickfire cycles and ever-changing demands are steadily killing job security.

Thanks to technology most of us have already been living with for upwards of 20 years, billions of people have a means of communication and influence without precedent, although our culture is now dominated by a tiny handful of omnivorous tech monopolies. Oh, and as all of this coheres, we are in the midst of huge demographic developments, such that by 2037 the number of people in the UK aged over 80 will have roughly doubled, to 6 million.

Clement Attlee, Tony Benn and Tony Blair do not offer much of a guide to this new world. The basic right-left divide – essentially, between those who believe inequality is a law of nature and are suspicious of collective action, and people who refute the first and believe in the second – will surely remain. But on both sides of politics, such profound shifts will trigger further shakedowns and splits. On the left, face-offs between “centrists” and self-styled radicals are likely to eventually die down: people on both sides will sooner or later either fail to adjust to new realities, or become aware of the hopeful possibilities within.

So what might the progressive politics of the 2020s and 2030s look like? Clearly, our most glaring inequalities call for action that only a powerful central state can carry out. We should start, at long last, to move tax policy towards concentrations of wealth and assets, not least land and property. The line should be redrawn between what ought to be considered public services and utilities, and things best left to the private sector, a point underlined by the nightmarish collapse of the outsourcing giant Carillion. Investment needs to be forcibly pushed into places long deprived of it.

Thanks to the statist instincts of Labour’s new(ish) leaders, Corbynism gets a lot of this stuff just about right. But, from the people at the top to its activist base, the party has so far failed to seriously develop another agenda, about giving huge amounts of power away. Right now, much of this is not easily translatable into electoral politics, but soon enough it will have to be, as the way we live changes at speed.

Because work and so-called welfare increasingly fail to provide any kind of secure foundation for living, one basic principle should sit at the core of the left’s vision of the future: that of a universal basic income (UBI). Thanks to the shadow chancellor, John McDonnell, there is a rather quiet Labour “working group” apparently looking into this, with a view to reporting around the time of the next election, and chatter about UBI periodically flares up at party gatherings.

But even as some people take tentative steps in the right direction – look at Scotland, where SNP, Labour, Green and even Tory politicians are putting together pilot schemes – UBI still feels like something that has yet to push beyond the edges of the left’s thinking. The kind of visions of “full employment” laid out in the Guardian earlier this week by Bernie Sanders too often highlight a collective failure to understand the possibility of a liberating politics of time and care with UBI at its heart – an idea that also speaks to the fact that an increasing number of us are going to have to combine work with the need to look after elderly family members and friends.

A basic income also goes with the grain of a digitally assisted world in which people have ever more capacity to do things for themselves. The modern profusion of things that are collective without being state-dependent (witness everything from Mumsnet, through memory cafes for people with Alzheimer’s, to after-school coding clubs) attests to people’s talent for making things happen; and the solutions they come up with tend to have deeper roots than most things imposed from the top. This element of how we live points to the future, and the empowered, self-organising impulse it represents will need to be incorporated into health, education, social care and more.

As evidenced by the new Scotland, the revival of Manchester and the arrival of the so-called metro mayors, it is also high time that towns, villages, cities, regions and the constituent parts of the UK were handed as many of the functions of Westminster as possible. As a start, the nasty, punitive Department for Work and Pensions should be dissolved, and its key functions handed to cities and local government. And the same should go for much of the meddlesome, penny-pinching Ministry of Housing, Communities and Local Government – though a momentous home-building drive will need at least an initial burst of momentum and funding from the top.

There is another centre of power that has only just started to get the right level of political attention. If you think Rupert Murdoch and the Daily Mail are still worth endlessly moaning about, think about a world in which 2 billion people use Facebook. The tiny handful of platforms that now dominate the internet are harvesting an ever-increasing mountain of information about the fine details of people’s lives, while they haphazardly distort political debate (Facebook’s move last week to downgrade the visibility of traditional news outlets will have no end of unpredictable consequences) and gobble up any start-ups that might threaten their dominance.

In response, the left ought to be laying the ground for something better, and applying the ethos of returning power to where it belongs. In the first instance, this would mean furthering the logic at the heart of new EU moves on personal data – the General Data Protection Regulation comes into force this May – and developing the idea that detailed material about how each of us lives is really part of our identities, and should be protected as such.

US writer and film producer Jonathan Taplin points out that in 20th-century America, the telecommunications corporation AT&T was allowed to be a monopoly on the condition that it spent a fixed proportion of its profits on research and development; in the 1950s, its patents were liberated, which triggered the rise of a new breed of start-ups. Unless new peer-to-peer technology begins to weaken the power of the tech giants, somewhere in that story is a pointer to what might eventually be done about the power of Google, Apple and Facebook.

Could a small and increasingly isolated country even scratch the surface of this stuff? Obviously not, unless it closely cooperated with other nations and governments, something that also applies to an issue both urgent and maddeningly absent: climate change, and the chronic need to use the pooled power of people and governments to finally address it. Contrary to any ideas that you can be both credibly progressive and happy with Brexit, that imperative points in only one direction: back to Europe. The future, when at last we decide to face it, will demand nothing less.

• John Harris is a Guardian columnist