Steve McQueen’s school photo will open a window on to our collective soul

I love primary schools, art galleries and London, so it’s not surprising that the news that artist Steve McQueen is leading a team photographing every year 3 class in the city, with the results exhibited in Tate Britain next autumn, filled me with cheer. Never mind that neither of my daughters, nor any of the London children I know best, is the right age – you have to have an eighth birthday between this month and August 2019.

Year 3 is the exact middle of primary school, if you count from reception to year 6. With all the capital’s 2,410 primaries invited to take part, not just parents but anyone with an interest in the city’s future will surely be intrigued by McQueen’s answer to what he called the “quite urgent” question of who, in the year of Brexit, we are.

Like Michael Apted in his classic Up documentary series, which followed a group of children from seven on, McQueen is explicit about his wish to explore issues of identity. “When you first start education, things start to change. When you start being aware of gender, when you start being aware of race. When you start being aware of class … it can actually change your thoughts forever,” he said. In a photo released with the announcement, McQueen’s is one of a handful of small brown faces in his class at Little Ealing primary, west London, in 1976.

To anyone who went to a similar school in the 1970s, there is pleasure in recognising the dress code of those days: fewer than half of McQueen’s class have on their grey jumpers; others wear the browns, yellows and stripes that were fashionable. But while memories may or not stir when we look at such images, the individual is not the point. Group portraits, whether of schools, sports teams or wedding parties, are all about belonging – something elite private institutions (and societies such as Oxford’s Bullingdon Club) have long known. McQueen couldn’t photograph everyone in London, or see into our future. No one would pretend even the grandest group portrait could mend our divisions, many of which are less visible than skin colour. But it is something to get a slice of the city on the walls of one room and present to visitors the idea: I am part of that.

These days, class photos feature hands on hips, arms folded, bodies turned this way and that. It will be curious to see whether McQueen sticks with the traditional format of his own school photo – teacher in the middle, children in rows – or is tempted to vary it. What surely hasn’t changed is the school’s reminder to look neat for what is a special moment (even if it is usually taken for granted and not much thought about). It is one in which children are posed, probably for the first and possibly for the only time in their lives, not as members of their families but as part of an institution.

What the 115,000 seven- and eight-year-olds will make of this, and to what extent they are able to be participants rather than just models, remains to be seen. But Tate’s project is not the only sign that national arts organisations are finally responding to calls to be more inclusive, and recognising that such initiatives must reach beyond discounted tickets, and on to stages and gallery walls.

Last month saw the first production of the National Theatre’s community programme – a musical version of Shakespeare’s Pericles. This week came an announcement by the Royal Opera House that it aims, after a £50m refit, to shake off its “elitist” image and be “open for a much wider public”, with plans including a talent festival involving schools.

While all the biggest publicly funded arts organisations have education departments, community arts groups and outreach workers have sometimes been regarded as the sector’s worthy yet poor relations. With so many dancers, actors and other artists already struggling to make a living from what they have been trained to do, no wonder it is hard to wrest resources away from them to spend on amateurs. But when the pool of people able to access such careers is known to have shrunk, and audiences for much publicly funded culture are notably whiter and older than the general population, it’s more important than ever that arts organisations work hard to bring in new people – not just to look at culture, but to make and do it.

For arts education, so squeezed by policymakers’ relentless emphasis on maths, science and literacy, McQueen’s project will surely be a fillip. If the attempt to represent London in all its diversity sounds didactic, even corny, I anticipate that the massed spectacle of childish humanity will be more surprising than that. Visitors from all over the place will leave with their idea of the city altered.

• Susanna Rustin is a Guardian writer and editor