The true scale of London’s housing crisis was revealed by last week’s “social cleansing” story. Inside Housing’s Jules Birch and Steve Hilditch’s Red Brick covered the topic admirably, and I don’t intend to rehearse the issues here, but it’s important to note that the story was not just about Newham. Most London boroughs are looking to export people from the capital because of the shortage of affordable homes and the expense or non-availabilty of private lettings.

Paul Bayliss, leader of the Labour group at Derby City Council hit the nail on the head when he said: “The solution for London is simple. The city needs more affordable homes.” He’s right of course, yet the deeper problem for London is not just a shortage of affordable housing but a shortage of housing per se, across all tenures and types. But even if London experienced a housing boom over the next decade it could still not build the homes it needs for the simple reason that it has run out of space.

Let me explain. According to the Office for National Statistics the capital’s population is set to grow from eight million now to over ten million by 2032. That means London will need to build at least 800,000 homes over the next two decades to cope with population growth – even more if it is to make good past under- supply. That means up to 40,000 new homes will be required every year for twenty years. Yet London is only building around 18,000 a year at present, and the HCA’s affordable rent programme will only provide 5,000 a year between now and 2015. What’s more, London has fewer than 4,000 hectares of brownfied land – barely enough for 120,000 homes. At the same time, 350,000 households are on London’s waiting lists and the vast majority of young Londoners simply cannot afford to buy a decent place to live. This all adds up to a housing crisis that can only get worse.

So the maths simply do not stack up. The truth is that London will never build the number of homes it needs unless it can expand upwards or outwards. Given that the days of high-rise residential blocks are in the past, and the fact that London has seen a startling increase in densification over the past twenty years it seems the only solution is outward growth. Yet our capital, in many senses the capital of the world, is confined within an outdated and artificial boundary – the green belt – which was put in place over 50 years ago and has no relevance to its current global status.

Again, let’s look at the facts. The 33 London boroughs cover 158,000 hectares but they are surrounded by an inviolate green belt of 479,500 hectares. But a further 35,000 hectares of green belt lie within the boroughs – 22 percent of London’s total area. Beyond the London boroughs, but within the M25, there is a further 75,000 hectares of land, of which about two thirds is green belt. So within the M25 there are at least 85,000 hectares of developable green belt land – that’s enough for over 2 million homes! Of course I am not suggesting that all of this should be built upon, but much of it is either low-grade agricultural land, or occupied by low priority uses such as golf courses and pony paddocks, with little or no aesthetic value and no access for the general public. You only have to drive around the M25 to understand that this land has no other purpose than to hem London within its post-war boundaries and you have to ask yourself, what is the point of preserving this land when London’s needs are so acute? Even if 50 percent of it was built upon it would provide over a million new homes, easily enough to accommodate London’s needs over the next twenty years. Across the UK, most towns and cities expand to the edge of their surrounding bypasses and ring roads. Why should London be any different?

Not only would this growth help to re-balance London’s dysfunctional housing market but it could provide hundreds of thousands of affordable homes. It would also allow London to think more creatively about its present shape and the quality of its environment. No longer would development be crammed into the capital at ever increasing densities. Green lungs could be pushed right into the heart of the city (imagine being able to walk or cycle from the centre of London to Epping Forest or the North Downs), brownfield sites could be turned into open spaces, allotments or city farms. The artificial and out-of-date distinction between town and country could be subsumed into a new garden city vision, where the country could be brought into the city. It would also give London the elbow room it needs to put in place a range of measures that would help to “green” the capital. For example, to create a proper network of cycle lanes so that the number of journeys made by bike could be increased from the present abysmal figure of 5 percent of all journeys towards Copenhagen’s 50 percent. Air pollution could be eased. A policy of outward growth could literally allow Londoners a breath of fresh air.

None of the candidates for Mayor has raised the issue of London’s boundaries and outward growth in their manifestos. They all appear to accept that London is a fixed entity, forever frozen within its decades-old boundaries. Boris Johnson even makes a specific pledge to protect the green belt. Yet cities grow and any credible candidate for Mayor should have a vision of how London will look twenty or fifty years from now. In my view, the only solution to London’s growing housing crisis is for the capital to push out towards the M25. If London wants to house, rather than export, its population there needs to be a public debate about growth and a recognition that the green belt is literally strangling our capital. London must grow.

(First published at Inside Housing 30th April 2014)