The government says it is preserving sporting facilities

In Keep Off the Grass, a report published on Wednesday, the party says there is an urgent need for more recreation grounds because of London's growing population and worsening obesity rates.

It says applications for developments on playing fields in London have more than doubled in the last four years.

The government should give strong, statutory protection to playing fields to prevent their loss, the report concludes.

Noel Lynch, London Assembly Green Party member, said new schools and privately-run sports facilities were being built on green sites.

"Fields once built on are lost forever", he said.

Rather than investing in schools sports fields, they (the government) encourage the selling-off of valuable resources to save government budgets Noel Lynch, London Assembly Member, Green

"Playing fields are vital to the well-being of Londoners.

They provide us with not just a place for sports, but also somewhere for walking or just to sit out in an open green space."

The report condemned the government and London boroughs for not doing enough to protect playing fields.

There have been 202 planning approvals for development on school fields in London since 1998.

Stronger regulations

"Rather than investing in schools sports fields, they (the government) encourage the selling-off of valuable resources to save government budgets", Mr Lynch said.

The report's recommendations include statutory protection to playing fields and recreation grounds, whether public or private, the renovation of existing facilities and the development of new ones on brownfield land.

It says school playing fields should not be disposed of unless alternative facilities are provided.