Michael Gove, the education secretary, has weakened the standards the previous Labour government introduced to protect school playing fields.

That is the view of shadow education secretary Stephen Twigg, who has waded into the ongoing row over school playing fields and the government's attitude towards school sports more generally.

Official figures show that between 1979 and 1997 - when the Conservatives were in power - as many as 10,000 playing fields may have been sold.

Conversely, during the Labour years of 1997 and 2010, some 213 playing fields were sold off.

"Parents want reassurances that these changes won't allow more to be sold off," Mr Twigg commented.

"If we are to ensure the Olympic legacy, the government must ensure that schools provide a decent amount of space for competitive sports and play."

The sale of school playing fields is seen as undermining efforts to reduce obesity, which costs the NHS billions every year.

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