Given the number of homeless people on Britain's streets, it is a national scandal how many homes are empty.
The Guardian reports on London mansions left to rot, and quotes this disturbing statistic:
One million homes are expected to be empty in the UK this year, despite 1.8 million Britons being on the waiting list for social housing, according to Inside Housing magazine's Empty Promises campaign
One way you can help is to support the Empty Homes Agency, an independent charity.
Inside Housing is also running a campaign against empty homes.
If you know a home which has been empty for several months, report it at the Empty Homes site.
In Waltham Forest, the borough which contains Walthamstow where I live, there are 2,715 homes empty according to the Department for Communities and Local Government.
This is a shocking situation. All political parties need to provide a response to the empty homes crisis.
Gordon Brown, David Cameron and Nick Clegg, what are your ideas to end this scandal?
Sheffield Social Centre squat evicted:
One way that empty properties are used is squatting.
Recently Pisgah House,a derelict listed building owned by the University of Sheffield, was squatted and turned into a social centre.
After eviction the social centre moved to a former National Health Service building, which they have also been evicted from.
Events that took place had included workshops on squatting and eviction, a reading group and a discussion on climate change.
You can see an interview with a member of the squatting group on the Forge Media website, which is the website for Sheffield University's student media, as well as a comment piece on the Sheffield Activist Network, who use the squat.
Good luck to the Sheffield squatters: those who are opposed to squatting should bear in mind that if leaving a home empty for a period of six months or more was made illegal then there would be less need for squatting.
Students at the University of Sheffield should also protest at the waste of an empty building as well as university funds used to evict squatters.
Leaving a building empty for a long period should be a crime when there are people sleeping on the streets.