07/02/2014 07:10 GMT | Updated 08/04/2014 06:59 BST

Unaffordable Housing Could Kill London

London homeowners are now in the absurd position of "earning" more from their homes than their jobs, with the average London price leaping to just over £450,000, according to the National Housing Federation.

London is gradually turning into a tale of two cities, says Brendan Sarsfield, Chief Executive of Family Mosaic

Earlier this month Nationwide revealed that house prices had risen an astonishing 14.9% in London during 2013.

London homeowners are now in the absurd position of "earning" more from their homes than their jobs, with the average London price leaping to just over £450,000, according to the National Housing Federation.

What's more shocking is that this frenzy isn't likely to let up: by 2020 the average London home is predicted to be £650,000 according to research from Oxford Economics.

The economy may be improving and unemployment falling but that most basic ingredient of life - housing - is becoming ever more restricted in our great global city.

Something is seriously wrong here.

How can we possible expect a family of two, a manual labourer or recent graduate to buy or rent when prices are this stratospheric?

I have always been aware of the plight of the least well off in securing good quality housing; what's fascinating to me is how, as the prices have spiralled out of control, the debate has gone mainstream.

In short, the frustrations and anguish of being able to afford to buy or rent in the capital are now something keenly felt by the middle classes.

People in well-paying professional services jobs are now struggling even to rent, and they are increasingly coming into contact with us via schemes such as shared ownership.

Yet despite the burgeoning crisis we still don't have an effective strategy to help Londoners.

The Mayor has promised to build 42,000 new homes a year, but hitting Boris Johnson's target will be impossible without radical change in our approach to housing.

Effectively, he is asking for a doubling of output, which will be impossible to achieve unless land, planning, political will, money, skills and resources are aligned.

If new homes aren't delivered rents will continue to rise and exclude more and more people from London. In an extreme scenario, the Mayor may even have to introduce rent control if they get too high, something more associated with America that the UK.

The consequences of inaction are stark and my worry is that London could emerge into two cities - like Paris - each occupied by two camps: the haves and the have nots.

This would destroy the vibrancy of London, making it a no-go area for millions of talented workers. It would have a devastating economic impact with people unable to afford to commute to places like the City or West End.

London relies on a steady stream of talented global citizens; it's partly what makes our capital so unique and why London was the world's most popular tourist destination last year.

So what is to be done?

First, we need an attitudinal shift from government. For too long housing hasn't been given enough government attention or financial support.

Health, education and large infrastructure programmes like Crossrail get far more support than housing - despite their being conclusive proof that good housing helps the economy and reduces demand for public services like healthcare.

Government must also recognise London's unique status. It is a world city and national policies aimed at the rest of the country often have an extreme impact on the capital, whether it's housing, welfare or Help to Buy, which is already having an inflationary impact.

Second, we need to go back to basics and recognise that social housing plays an important role in helping those on the lowest incomes and keeping rents affordable for all.

It already houses almost 20% of Londoners. What we need is greater funding to invest in homes for ordinary and middle income Londoners, young graduates and couples and to use the existing social housing stock differently.

Social housing is also critical to the revival of the British economy and in creating a socially cohesive, stable and aspirational society.

As well as affordable rents, social housing providers play a role in helping tenants find work and come off benefits. In turn, employed people help generate tax revenue, create wealth and reduce demand on public services.

Too many of these broader arguments around housing are lost in the often repetitive debate. But we must make the argument more strongly to policymakers, who ultimately decide how much support social housing gets from central government.

London is the greatest city in the world. We love it because of its accessibility, diversity and vibrancy. But this reality will disappear if we can't make housing more affordable for everyone.

The very character of London is on the line - let's act before it's too late.

Brendan Sarsfield is Chief Executive of Family Mosaic, one of the largest social housing providers in London and the South East, which provides homes for 45,000 people.