Restrictions on sales were introduced in 1998

From now on schools and local authorities will have to show that selling the land is a last resort.

They will also have to use the cash raised to improve other outdoor facilities before any money can be used on indoor projects.

Fewer school playing fields have been sold since 1998 when rules governing such sales were introduced.

Councils that want to sell a school playing field already have to get the permission of the education secretary.

And they have to show that the land is not needed by other schools or the local community.

Last year, 17 applications were made in England and nine were approved. This was down 20 on the previous year.

Community

Under the new rules, new sports facilities must be sustainable for at least 10 years, to ensure they are available to pupils for the long-term.

The government worked with the campaign group the National Playing Field Association (NPFA) to draw up the guidelines.

The body had clashed with the government in the past, saying the country was losing too many playing fields to developers.

Education Secretary Charles Clarke told Radio 4's Today programme there were around 25,000 playing fields left across the country and that all these would be protected:

He said: "We have already stemmed the tide of playing field sales that took place before 1998, and I am grateful for the support of the NPFA in further strengthening our guidelines.

"This means that school playing fields will now not only be protected but also improved for the benefit of pupils and the wider community.

"It should also challenge the misconception that school playing fields have been sold off indiscriminately."

Monitoring

Mr Clarke said the changes were being made because he was not satisfied with the way the existing rules were working.

But he pointed out that before 1998 there were no rules governing sales.

The education secretary said since 1998 of 194 applications to sell playing fields, 33 were either rejected or withdrawn, 60 were approved at schools which had been closed and 88 were approved at schools which remain open.

The director of the NPFA, Elsa Davies, said: "On my last day in post, it warms my heart enormously to know that in future school playing fields will be lost only in the most extreme circumstances and even when this happens, the income will be used to improve outdoor play and sports facilities.

"I leave the NPFA mightily heartened that the government is serious about protecting school playing fields."

But former sports minister Kate Hoey told Today: "This will only protect the larger playing fields. It's not going to protect the smaller school playing fields."

However, the Department for Education and Skills said the rules would apply to all playing fields.

'Belated action'

Good monitoring of the process was very important, she added.

Liberal Democrat culture, media and sports spokesman Don Foster said this "belated action" was welcome but should not blind people to the fact that "too few children have the opportunity to do sport at school".

"The government wants kids to do two hours of sport a week, but too often this is not in curriculum time," said Mr Foster.

"The major problem is that kids are not given a broad range of sports to choose from.

"Unless the government address this problem, then 70% of children will continue to drop out of sport completely after they leave school."