Around one person in seven in England are living in unaffordable, insecure or unsuitable accommodation.
The claim comes from the research produced by the National Housing Federation, which says the problem affects “people of all generations and in all parts of the country.”
The study claims that more than 3.6m people are living in overcrowded homes while 2.5m people can’t afford their rent or mortgage.
Another 2.5m adults are stuck living with parents, with an ex-partner, or with friends because they can’t afford to move out. Overcrowding is considered to be particularly bad in the south of England because younger generations can’t afford to move out.
It claims that the actual number of people in England who need social housing (3.6m) is almost double the number on the government’s waiting list.
The NHF also says the country needs 340,000 new homes every year - more than the 300,000 put forward by many analysts to date - including 145,000 social homes.
In a joint campaign, the National Housing Federation, along with Shelter, Crisis, the Campaign to Protect Rural England and the Chartered Institute of Housing wants the government to build these social homes by investing £12.8bn every year for the next decade.
“This crisis cannot be solved by tweaks around the edges of the housing market. What we need is a return to proper funding for social housing, to the levels last seen under Churchill. Investing in housing is a win-win for the government - it would bring down the housing benefit bill, provide everyone with a secure and stable start in life, and kick start an economic boom creating thousands of jobs” explains NHF chief executive Kate Henderson.