We all know the cliches. We may love them too, those curtain-twitching, privet-trimming, social-climbing, car-washing, amusingly neurotic, sometimes adorably eccentric suburbanites. They are Surbiton's Good Life neighbours, Purley's Terry and June and Tony Hancock of the (by then non-existent) East Cheam; Hanif Kureishi's Bromley Buddha, even, arguably, Streatham's homely Madame Cyn; the inhabitants of Betjeman's Metroland. Here are people and places easily patronised and tenderly teased for their steady decencies and small hypocrisies in the commuter borderlands between countryside and city roar, where grey merges into green and forms a state of mind.

But even clichés change. And the suburbs themselves, for all their reputation for prim protectiveness, are not immune. Dig into the right data and find firm evidence that popular culture needs to adjust its assumptions and its aim. For a start, suburban territory has got more crowded - the 2011 census found the population of Outer London to be approaching five million, which is half a million more than in 2001. The classic attraction of the suburbs is that they provide more space, but far more people are now crowded into them.

There's also been an ethnic diversity shift, with the proportion of Outer Londoners who are white falling from 74% in 2001 to 61% in 2011 and projected to fall to 54% by 2021. The mix of housing is altering fast too. During the same ten-year period the number of owner-occupied homes fell, reversing a strong upward trend that had held for decades past. The percentage fell from 68% to 60%. Private renting, meanwhile almost doubled to account for 21% of Outer London housing compared with just over 11% in 2001.

Poverty has become more prevalent amid the leafiness. A recent London School of Economics report shows that poverty rates have increased there throughout this century, accentuated by the recession, which hit Outer London harder than Inner London. The Trust for London's poverty profile reveals that 58% of the 2.1 million Londoners in poverty now live in Outer London compared with 50% ten years ago. The comedy of the suburbs, so dependent on the small snobberies of upward mobility, isn't quite such light entertainment any more.

These are just a few broad brush strokes of a much larger picture containing wide variations and a range of definitions. Some parts of Outer London would not match everyone's idea of what a London suburb is, while several settlements outside Greater London would. The Outer-Inner distinction itself is made in different ways. Newham and Haringey, for example, were deemed part of Outer London when the capital's 32 boroughs were created by the Local Government Act 1963, but how much do they have in common with Richmond? The census and Office for National Statistics count both as part of Inner London, and, unlike the Act, place Greenwich in the Outer category. But even when generalised, certain trends are clear and have big implications.

Extreme manifestations of London's housing crisis are occurring in Outer London areas. A forthcoming report from property consultants CBRE will anticipate big shortfalls in housing supply in an array of Outer London boroughs, including Enfield, Redbridge, Richmond, Merton and Kingston. It expects the problem to get worse as more people find Inner and Central London prices too high and look further afield.

Meanwhile, more and more households who rent their homes are turning to housing benefit to make ends meet. Research from London Councils has found that while the number of claimant households in Inner London fell by 1,571 (2%) during 2012, it rose by 11,663 (9%) in Outer London of which 10,454 contained people with jobs (90%). The largest rises in claimant households occurred in Barnet, Enfield, Croydon and Brent, with only Waltham Forest seeing a small one. In Outer London as a whole there was a very significant rise in the number containing dependent children – an additional 8,846.

Is this evidence of the dispersal effect that critics of the government's housing benefit predicted, with large numbers of poor London families obliged to move out to cheaper areas? London Councils says it might not be possible to reach a definite conclusion. The LSE researchers said much the same about Outer London's increased poverty rates – it could be due to people moving from Inner London because it was becoming too expensive, to newcomers settling there for the same reason, to long-standing residents becoming worse off or some combination of all three.

Whatever blend of factors is driving all these changes they fit part of a wider cost-of-living theme London's politicians will seek to address as May's borough elections approach. Labour, hoping for gains, has made a conspicuous start, with five of its six prime targets being in Outer London – the finely-balanced councils of Croydon, Merton, Redbridge and Harrow along with Barnet of "easycouncil" fame (the Tories there, of course, have other ideas.)

Sadiq Khan, Labour's shadow London minister who is in charge of its election campaigns in the capital, says there are fewer jobs in Outer London than there were and that wages there are falling. He claims Ed Miliband's pledges on housing and energy bills "have really resonated in these areas." Labour will also be on the attack on parking and transport costs, in the latter case spurred by Boris Johnson's latest fares increases, which come into effect today.

All of these contests for votes will have their own character, reflecting local as well as national concerns, and each will illuminate further episodes of the longer story of suburban London, its pleasures and its discontents alike. To close, here are a couple of You Tube clips capturing very different parts of how that story has been told. First, the (rather blurry) opening sequence of Terry and June.

Enjoy those glimpses of the old Whitgift shopping centre while you can. A finally, a memorable note of dissent from The Members.

The 2011 census data includes a wealth of demographic data about Outer London, including stats on individual boroughs. More detail on the housing changes I mentioned above can be found in table 13 here and on the mix of ethnicities here.