‎You graduate from university with a first class degree and land your dream job in a creative industry or media. It’s based in London, voted the best place in the world for quality of life. Your salary is £24,000 per annum, in line with the average graduate salary in the capital. Over the summer you manage to navigate round the “fake listings” on Rightmove, find a landlord who will accept an as-yet-unemployed tenant, and cobble together the thousand quid you’ll need to pay your deposit and various estate agent fees. Hard bit done and life sorted, you think smugly to yourself.

Except it’s not. Because assuming that you and your flatmate are looking for an “average 2 bed Zone 3 property”, £1,060 of the £1,500 you will take home each month is marked out for rent. On top of this, you are obliged to contribute c. £150 to household bills and fork out £148 a month for a Zone 1-3 travel card. In the third most expensive city in the world, you are left with £142 per month to save, eat and socialise.

So what do you do? You break the mould, say no to London, and settle for another job elsewhere. And slowly, as your contemporaries cotton on, media outlets start to realise that they’ll scoop up better graduates if they migrate to other parts of the country. It doesn’t take long before the smaller publishing and tech companies follow suit. Then, the edgy, independent restauranteurs responsible for London’s “eclectic food scene” flee Peckham, Hoxton and Brixton in pursuit of their customers. Ripples reach the suburbs, and the twenty somethings who have spent years gamely commuting in to central London from Purley (it’s the new Balham, which was once the new Clapham which was once the new Chelsea, don’t you know) decide they’ve had enough. All of a sudden, London has lost some of its sheen.

It may sound a far-fetched scenario, but there is a febrile mood in the city at the moment and with alarmingly frequent terror attacks, a growing anti-establishment feeling, and extortionate rent, all the conditions are in place for some kind of youth exodus.

Unfortunately, at this particular juncture, having a thriving, young capital is more important than ever before. We scoff merrily at the idea of Frankfurt replacing London as the home of Europe’s financial services post Brexit because we have total faith that London’s vibrancy and vitality will carry us through. Yet the virtues of vibrancy and vitality are not bestowed upon London from on high, they are the product of youth, energy and creativity. Squeeze the creative types out of the capital, and you are left with a sanctuary for wealthy bankers and consultants. And a sanctuary for bankers and consultants is a place no one wants to live, perhaps least of all the bankers and consultants.

So what’s the answer? Affordable housing built on the space available to us. Which means, of course, breaking down the taboo and having an open and honest re-examination of the London Green Belt. A report by London First, a think tank which advises government on enhancing London’s competiveness, proposes that: “local planning authorities should be encouraged to review their Green Belt and consider how the land within it that is of poor environmental quality, of little or no public benefit and has good connectivity could be re-designated for high quality, well-designed residential development that incorporates truly accessible public green space.” They are not advocating paving over Regent’s Park. They are suggesting that during a housing crisis, agile thinking is required, and refusing to build on principle is perverse. When 7.8% of the London Green Belt is given over to golf courses, it is plain the 1960s initiative needs some modernising.

When the government’s housing white paper was published earlier this year, it seemed like we were on the brink of opening these difficult but necessary discussions. The white paper, “Fixing our Broken Housing Market”, outlined some bold and sensible reforms which included allowing local authorities to build on the Green Belt after “all other viable options had been considered”. Yet like so much else from early 2017, it is now being said that these reforms will be kicked into the long grass. Having squandered her majority, Theresa May is shackled by her home counties’ MPs who will fight to ensure that ugly new homes don’t spoil their pretty English villages.

But it is right that these MPs should not be dismissed, because their objections illuminate a very important issue – and one which gets to the heart of British squeamishness about building affordable homes. We always build ugly. Just after the Blitz, when hundreds of thousands of Londoners were homeless and the country was in danger of sinking into a deep recession, it was decided that when building new homes, speed of erection should trump aesthetics and durability. In 1947, it may have been a sensible policy: now, it is not.

Create Streets, a social enterprise set up to advise the government on the built environment, argues that in 2017, the case for building traditional, pretty, terraced streets is empirical. They claim, and the evidence backs them up, that in a contest between tower blocks (the go-to government choice for affordable housing) and streets of terraced houses, the latter wins on every front. For a start, terraced houses provide people with what they want, meet with minimal local resistance, and are cheaper to maintain. But what’s more, recent research proves that due to the wasted space between existing tower blocks and the inefficiencies of estate layouts, conventional terraced streets of houses and low rise flats can actually almost always match their population densities.

The situation is desperate. Of course it is important for Londoners to have access to green space, but it is time to think creatively and recognise that a rigid belt around the boundaries of a growing financial hub may now be anachronistic. If the capital doesn’t start providing for young people soon, London is in danger of becoming boring, and in the words of the late, great urbanist Jane Jacobs “when a place gets boring, even the rich people leave”.