Councils should tackle the housing shortage by taking over empty homes, a charity said.
The Empty Homes Agency said the downturn in the housing market and a steep rise in repossessions had caused a record number of homes in England to become vacant.
It also blames the increase on an over-supply of new-build flats in some city centres and housing regeneration projects that have stalled because of a lack of funding.
The 2004 Housing Act allows councils to seize homes left vacant without good reason and rent them out for social housing.
The charity wants the public to report run-down, empty homes to its website - reportemptyhomes.com - which automatically informs councils about the properties.
Chief executive David Ireland said: "At the very time people need more homes, record numbers are falling empty.
"There are now enough vacant homes in England to house almost two million people - yet far more attention is paid to building new ones.
"Councils have the power to step in and help, but can't do so unless they know where they are and won't unless they know people care."
He added: "If everybody who is affected by this growing problem reported just one empty home it would provide a huge impetus and send a huge message to government and councils that action is needed now."Reuse content