Four square miles of green belt are lost to developers every year, according to the Campaign to Protect Rural England (CPRE).
An area of green belt land the size of Bath has been lost to housebuilding since 1997 said the CPRE.
Their paper: "Green Belts – Robustly Protected Or Under Threat?", CPRE says that "Between 1997 and 2003 an average of 1,100 hectares – nearly four square miles – was lost each year," and all this despite the fact that, "the Government has repeatedly stated its commitment to protecting the Green Belt".
CPRE slammed the the Department for Communities and Local Government (DCLG) for its failure to prevent greenbelt development.
"Since the creation of DCLG in May 2006, the Secretary of State has decided 48 planning applications involving development in the Green Belt. From these, 16 significant developments, involving the loss of at least 450 hectares of Green Belt, have been allowed," read the report.
The DCLG provided the figures for the research, from their Local Planning Authority Green Belt Statistics, published in January 2008. The department however questioned how CPRE assessed their figures.
A CLG spokesman said that this figure was also misleading. "What they [CPRE] don't tell you is that of those cases, nearly half of them were overturned attempts by local authorities to develop green belt sites. This government has delivered 75% of its housing on brownfield sites."
Planning Minister Iain Wright said: "This analysis is flawed and one sided. The suggestion that the amount of Green Belt is falling overall is deeply misleading. What the CPRE fail to tell you is that since 1997 the overall amount of green belt has grown by 82,000 acres (33,000 hectares)."