Almost 14,000 acres of Green Belt land - the equivalent of 80,000 football pitches - have been lost to development since Labour came to power, figures have shown.
Essex, Kent, Cambridgeshire and the London suburbs, where there is a high demand for housing, have seen the greatest amount of protected countryside disappear.
The Midlands and the North have also been affected. Nearly 4,000 acres have been lost in Leeds.
The figures were made public by ministers following questions by Eric Pickles, the Conservative communities spokesman.
Gordon Brown has pledged to protect the Green Belt despite his plan to build three million homes over the next 12 years and protected land has been expanded in some rural areas, particularly in Yorkshire and the South West.
A spokesman for the Department of Communities and Local Government said the Green Belt had grown by 64,000 acres since 1997.
