Things have changed! It's official! The census confirms what anyone with eyes in their head surely knows: things are not as they were 10 years ago. We have become more "foreign", less religious, less married, more likely to be renting than buying houses. This is us all right. Heathen swingers destroying the notion of Britishness.

The language of the census is strange, though. I don't think I have used the words "foreign-born" before but there are 3 million more "foreign born" people living here than there were in 2001. The concern over the percentage of the population describing themselves as "white British" is tangible. The right spins this as Labour's lax immigration policies, which were designed to produce Labour voters. This is simply not true. To deny the impact of this wave of immigration is equally disingenuous. People feel this in all sorts of ways, primarily through their pockets. Wages are driven down. Globalisation does this. War does this. Recession does this. But it's easier to blame your neighbour.

Yet we are stuck with the old words to describe new worlds: "melting–pot" and the coded "urban" or "vibrant" to describe cities in which all kinds of people live. I live in London but I leave it often enough to know that parts of the country are pretty white, enough to scare my "white" children because they are just not used to such a monoculture and find it disturbing, unreal and, to be frank, lacking.

I think of their anxiety in reverse when I try to imagine the inner world of a Nigel Farage type – a dirty job and all that – but I suppose in the golfclub of his mind, real Britain must properly exist only outside the M25 and be entirely populated by booming men who are rather too pleased with themselves. So I can see that many cities must now make him uncomfortable.

The ease with which people who are "different" fall in love and have babies that can no longer tick the sacred "white British" box must be worrying. This universe is indeed foreign to me not because of any profound anti-racism but because things have so self-evidently changed in my lifetime. I had to explain the term "mixed race" to my youngest the other day, as she insists it's "mixed raised". She may have a point. "Diversity" isn't a theory but a practice for younger generations. It's not some utopian "melting-pot": there are all kinds of difficulties that are negotiated on a daily basis. That's life.

But there is in the reaction to the census a mourning for a "unified national way of life". What is this when it's at home? According to Douglas Murray, the British way of life "becomes simply one option in a set of lifestye choices – something you might adopt if you care to, but only in the way you might take up yoga or swimming". To which one can only answer that some people like yoga and swimming. It keeps them flexible.

Identity is at the heart of this "what have we become?" cri de coeur of the cultural right for whom much of the modern world is a baffling place. Many of us aren't going to church, we don't believe, we cohabit. We could claim this as our true native state. But there is a fight on about how we see ourselves. Hence the ludicrous spectacle of the Tories offering gay marriage as a signifier of modernity. This might be more credible if it came from a government that has any sort of drive to equality in its other polices. David Cameron could have chosen to "modernise", for instance, around the decriminalisation of drugs, but has decided that the institution of marriage needs strengthening and it must be gay people who do this. In yoking social liberalism to innate conservatism we get this botch where inequality in the church cannot be challenged. That this is the final straw that Ukip will exploit becomes hilarious. As was the sight of various backbenchers indulging in their rather obsessive pastime: discussing buggery.

Still, if anything, what the census shows us – and this has been apparent in the sight of mostly middle-class men discussing other people as though they were aliens – is that not one of our institutions is at all representative of the country we are now. Parliament isn't, the church isn't, the media certainly isn't.

Thus the usual claptrap about "diversity" being something to celebrate is meaningless when it is not publicly acknowledged. "Diversity" cannot be acknowledged when we don't have one major institution in the land that reflects the makeup of our country. We are a long way off in terms of gender, a huge way on ethnicity and above all in terms of class.

What remains truly "foreign" and a massive failure, is that over the past 10 years, none of our key institutions have managed to transform themselves in any meaningful way. If anything, they have become narrower, whiter, more male and more elite. The county has changed, the structures that run it should reflect who "we" are. They simply choose not to. They are not us.