Nearly two million Londoners could be driven out of their homes and out of the capital by the cost of housing, according to research from housing charity Shelter.
The figures, published to coincide with the launch of their campaign to press the capital's next mayor prioritise housing, show 30% of Londoners - the equivalent of 1.8 million people - are afraid their rent, mortgage or the cost of upkeep could drive them out of the city.
Shelter's survey, conducted by YouGov also shows 65% of Londoners who rent don't believe they will ever be able to afford their own home.
Campbell Robb, chief executive of Shelter, said something needed to be done to "fix London's housing" to avoid an "exodus" of families: "We need the next Mayor to give London’s housing the same leadership and profile as we see for transport. This means bringing together a complex web of budgets and departments into a simple, public-focused agency that can drive the change we need.
"We want Londoners to join our campaign and challenge the Mayoral candidates on how they plan to use the new powers over housing to ensure that all Londoners have decent, affordable homes."
In response to the survey London mayoral candidate Ken Livingstone agreed their was an "urgent need" to build more homes in London: "With just 56 housing starts in six months last year, Boris Johnson has failed to act for Londoners and the capital is in the grips of a housing crisis.
"It is vital to the future of our great city that people can afford to move to London and make their home here. As well as building more affordable homes, I am committed to delivering a London-wide social lettings agency, and campaigning for a London Living Rent."
A spokesperson for Boris Johnson's campaign said: "Just as with the Tube, Ken Livingstone's own party did not trust him with London's housing.
"But Since 2008, Boris Johnson has persuaded No 10 to hand him the powers, he has secured £3bn of investment and 500 hectares of public land despite tough economic conditions and is delivering a record 50,000 affordable homes, creating 100,000 jobs while strengthening the protection of green space and back gardens.
"With funds scarce we have to avoid building a new bureaucracy. We all know what is needed - more houses and that's where Boris will focus every penny."