One-in-three people would struggle to pay their rent or mortgage within a month of losing their job, a charity has warned.
Some 35% of workers - around 8.6 million people - do not have enough money put aside to meet their housing needs beyond four weeks, a YouGov poll for Shelter found.
Around a fifth of Britons - roughly 4.4 million people - would be at risk of becoming homeless immediately.
Campbell Robb, chief executive of Shelter , said: "These figures paint an alarming picture of a nation where the buffer between having a home and potentially becoming homeless is a single pay cheque.
"Millions are living on the edge of a crisis, only secure in their homes for a matter of weeks.
"At the same time, support for people who have lost their homes is being stripped away.
"It's easy to see why every 15 minutes, another family in England finds themselves homeless."
The survey of 2,000 people found families with children would fare even worse in the event of redundancy.
Around two-in-five parents said they could not afford to pay for their home for more than a month, while a quarter said they could not meet their payments at all.
The Department for Communities and Local Government pointed to figures from the Council of Mortgage Lenders , which show repossessions are at a five-year low and falling.
However, a spokesman added: "We are not complacent and would urge anyone facing financial difficulties to seek early help to avoid losing their home.
"We have one of the strongest safety nets in the world against homelessness, bolstered by £470m Government cash and extra flexibility for councils to help those in need.
"We've also put help in place, including the extended £221m Mortgage Rescue Scheme and funding for organisations including Shelter, to provide information and advice services."