Heatwave: Lazing on a sunny afternoon

Urban planning can make spontaneous interaction between strangers of the kind that blossom – or explode – in the heat either easier, or harder

Women sunbath in Green Park, London. Britain is in the midst of its first heatwave for seven years, and there is no sign of the mercury plummeting any time soon (PA)

This is the time of year when wars break out, wrote Cyril Connolly in 1938, with Europe as tinder dry and close to conflagration as the parched hills of his beloved South of France.

Thank Nato, or the EU, or your saviour of choice, but now a long heatwave at these latitudes kindles only tetchy local quarrels. They can still burst into flame. Especially for an urban people used to indoor refuges from damp or cold, outdoor life in crowded public areas tests the resilience of our al fresco etiquette. High temperatures and tight spaces can mean that sociability under blue skies descends into an irascible struggle to win and keep a scorching patch of urban ground.

Milling pavement crowds outside separate pubs may fuse into a kind of clinking, braying ratking (that gruesome knot of rodents entwined by their tails). Passers-by find themselves forced into the traffic or (as happened to me by the river at Richmond last weekend) almost into the Thames. City squares and parks morph into terrains of silent combat where territorially minded loungers and picnickers compete for an ever-shrinking patch. The latest weapon in this sun-struck turf war is the plastic gazebo, that portable land-grab disguised as garden furniture, which allows every aggressive bunch of lunchers to colonise swathes of shared ground like maharajas under a shamiana. Meanwhile, cafés and restaurants push – or break – the limits of licences that grant them only a thin strip of pavement for outside tables. Sun-strafed streets can become an ill-tempered battleground rather than the site of some polite passeggiata.

Al fresco living, above all in fierce heat, needs rules and guidelines – not so much inscribed in by-laws as built into the design of urban space. By a strange stroke of meteorological fortune, this week the Royal Academy launched an exhibition to mark the 80th birthday of “starchitect” and masterplanner Richard Rogers. All around, in the streets and squares of a sweaty London, residents and tourists fought to convert a cold-weather urban landscape into the sort of all-day public stage that Rogers lauds in the cities of Renaissance Italy.

In the BBC profile shown (or rather, hauled out of the vault) to coincide with the RA show, Rogers went to Pienza in Tuscany – the 15th-century prototype for the kind of citizen-friendly architecture that supposedly encourages us all to come out and strut our stuff in an open-air theatre of community. Ah, Pienza. I visited a year ago, and very pretty it is too (although quite as full of swanky trattorie and souvenir boutiques as you’d expect). But this is, and always has been, strictly controlled ground. The dinky little city on a hill began as the toytown utopia of local boy made good Aeneas Silvius Piccolomini, who became Pope Pius II. In the 1460s he razed his home village of Corsignano and put his theories of humanist architecture into stone-and-marble practice. Yes, Pienza was Poundbury (Prince Charles’s own model town) in the Val d’Orcia.

Urban planning can make “spontaneous” interaction between strangers of the kind that blossom – or explode – in the heat either easier, or harder. In the Renaissance tradition, Rogers himself argues that cities exist not only in their buildings but in the spaces between them – “rooms without walls”, as the manifesto for his practice says. In his design for the National Assembly of Wales on Cardiff Bay, Rogers subverts the usual sombre temple-like aura of parliaments by throwing a light pavilion-style roof out towards the waterfront and inviting everyone to come in and look, rest or play. Here as elsewhere, he aims to fashion the sort of boundary-free public parlour or salon that nudges users to acknowledge one another’s presence but also to respect boundaries.

You can’t, as our fractious jostling in the heatwave proves, implant this kind of congeniality simply by clearing space. We all know the forlorn “squares” that disfigure 1960s new towns or post-1980s shopping precincts: not theatres for conviviality but dead zones that attract (at best) skateboarders and taggers, or (at worst) muggers and dealers. Herding the masses on to desolate parade-ground expanses hardly counts as Tuscan togetherness. Martin Amis’s satirical novel Lionel Asbo has a dismayed glimpse of simmering “Carker Square” in his hellish outer suburb of “Diston”, “two swathes of brown grass the size of football pitches … and the crazy-paved spoke-shaped walkways converging on the defunct fountain”. Here the Distonites gather like “random wanderers in the aftermath of an earthquake”. Make allowances for the Amis flick of misanthropy, and we’ve all been there – especially when the mercury rises and the pubs heave.

But don’t – unless you have Amis’s talent for excoriation – blame the people. A baking summer in the city exposes just what works, and what fails, in the management of public territory. In London, the riverside walks along the South Bank from Waterloo to London Bridge have reclaimed the river for the people. (Rogers wanted to do the same along the northern embankment too.) On the other hand, it’s still a disgrace that only one side of Trafalgar Square is traffic-free.

Smart planning can nurture our summertime sociability. And urban makeovers need not be for ever. Today is the inauguration of the Paris Plage scheme – the annual wizardry that for a month every year transforms a stretch of the Seine’s banks into an ad hoc beach. In London, the customising of iconic sites into Olympic venues showed what might be done. If we can’t have annual beach volleyball on Horse Guards Parade, how about a kids’ playground with an outsize, outdoor Grand Café attached? It would beat the last non-royal use of that terrain: a promo concert last month for Brad Pitt’s apocalyptic epic World War Z. Even in this heat, we’re not quite mindless zombies yet.