There are two kinds of questions to be asked about Brexit. One of them defines the day-to-day grind at Westminster, and is about an urgent set of issues that encompasses everything from the most basic framework for trade to the future of Northern Ireland, and which still seem all but insoluble. But as all the parliamentary drama on goes on, it is the other big Brexit conundrum that shows even fewer signs of resolution. To use a phrase habitually deployed by the prime minister herself, what kind of country do we want to be? Put another way, who are we?

To some extent we know the answer, and it is not pretty. Whatever the varied motivations of many of the people who voted for it, our exit from the European Union looks to outsiders like an expression of nostalgia, introversion and a very unbecoming belligerence. Some of the most powerful branches of government seem to be operating on much the same impulses. As evidenced by the Windrush scandal and a steady stream of heartbreaking deportation stories, the Home Office now seems to be institutionally sociopathic. So does the Department for Work and Pensions.

The public gets what the public wants, even when it ruins the lives of many of the public themselves

Of the countries that make up the United Kingdom, England has come to be understood as a country awash with furies and resentments. Politicians have seen that a significant part of its population apparently thinks that immigration is inherently problematic and ought to be the focus of endless crackdowns, and that supposed benefit “cheats” deserve the same treatment. In turn, the Tories – and, it has to be said, elements of the pre-Corbyn Labour party – have only encouraged the same prejudices and misapprehensions, so the public gets what the public wants, even when it ruins the lives of many of the public themselves. The central tragedy of Brexit, perhaps, is that it represents such crabby, self-harming attitudes being applied to the fundamentals of economics, trade, and Britain’s place in the world.

When I am out reporting, it usually seems that most of us remain essentially mild, moderate people, seemingly open to compromise. But everyday examples of the worst of the Brexit spirit are easy to find. Last week, I visited the offices of a successful language-learning app in central London, and talked to staff who had moved to the UK from across Europe, and who had recently started to experience a mixture of discomfort and estrangement. The Austrian chief executive told me that he had been upbraided by a complete stranger for speaking his native language: “I was talking in German on the phone, and an old lady, very well-dressed, came up to me and said, ‘Speak fucking English’.”

We all know what sits behind such small horrors. The belief that millions of people come to this country to swing the lead and somehow milk the system is a commonplace. There are benign manifestations of England and Englishness, but in certain people’s mouths those words express whiteness, a defiant rejection of the outside world and the cities that have opened themselves to it. Some still believe that their country needs to rediscover its imperial supremacy, stand apart from Europe, and stick it to the rest of the world. There are hardened versions of these views on the outer edges of the political spectrum, and vaguer echoes that blur out into the mainstream. But they are real, and they are at the heart of where we have arrived.

Play Video 14:49 Brexit breakdown: southern discomfort – video

On the left, there is an age-old tendency to hear people talk about things that stray into questions of culture and identity, and automatically reduce them to matters of economics and inequality. In this view, people might complain about immigration but what they are really brassed off about is the housing crisis; when they talk longingly about the past they are essentially bemoaning the demise of manufacturing. As a recent speech by Jeremy Corbyn put it, the only divide that supposedly matters is that “between the many – who do the work, who create the wealth and pay their taxes, and the few – who set the rules, who reap the rewards and so often dodge taxes”. To the extent that England’s malaise is tangled up with a serious shortage of homes, deindustralistion, and our country’s awful imbalances of power and wealth, this is hardly unreasonable. Indeed, I have seen plenty of evidence of the deep connection between the two, and regularly arrived at the same conclusion.

There again, why do much the same Brexit-ish instincts and opinions run so deep among affluent people with no obvious axe to grind? What students of Marxism would call economic determinism has its place, but it risks constant denial of the fact that politics has long since slipped free of the old simplicities of class and economic complaint. Culture matters. The political right understood this a long time ago, selling a brand of Englishness replete with the reactionary instincts that exploded in June 2016. In his brilliant Brexit book The Lure of Greatness, the writer and activist Anthony Barnett makes a point that people on the left ought to think deeply about: “One reason the right won such dramatic successes in 2016 in England is that their opponents on the left fled the field of meaning and identity.”

Five years ago I watched a grassroots movement in Scotland lead a conversation about leaving the UK behind, and moving on from an old, patriarchal, hidebound view of their own country. People I met had developed a kind of progressive politics that could deal with the two key challenges of modernity – identity and belonging on one side, and equality and redistribution on the other – and incorporate them into a vision of a forward-looking, open country. The Scottish independence movement had its nasty elements, not least online. But after long years of groundwork, the conversation about a new Scotland had been updated by a coalition of organisations that stood well apart from party politics, known at the time as “the third Scotland”, because of its distance from both the SNP and the Labour party.

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Coming back home feeling both envious and excited, I wondered if my country could give rise to anything similar. I know, I know: England might be too big, weighed down by its history, and now fatally wounded by its deep divisions. Even though it has its own health service and education system, and an array of problems that originate in the broken way it is governed, almost no politicians on the left will talk about it. But 55 million of us live in that country, and if we believe it should finally embrace the values of diversity and acceptance and an open and connected world, we are going to have to make that case.

As against imperial delusions and English exceptionalism, it is time we talked about the realities of our past and a future that necessarily involves being part of Europe – and the fact that in the 21st century, the movement of people is a basic fact of life. I know what a modern, open, accepting, diverse vision of my country looks like: I see it not just in Bristol, Manchester, Leicester, Leeds, and Birmingham, but in endless small kindnesses in places that are too often either ignored or reduced to a Brexit-supporting caricature. We need to seize on such examples and make the case for a new England. When do we start?

• John Harris is a Guardian columnist