Garden Organic (the working name for Henry Henry Doubleday Research Association) have launched a campaign to stop ‘garden grabbing’ by property developers.
Basically, this is where developers snap up a large detached property and then get rid of it. The land is then fully built on to create a load of new houses (small, rubbish ones no-doubt!).
They have launched a petition here asking the government to change gardens from being defined as brownfield sites, thus preventing gardens being annihilated.
There is an overview of the main issues and other ways you can help on the Garden Organic website.