Playing fields row explained
17 August 2012 Last updated at 16:59 BST
The Department for Education has apologised after giving inaccurate figures about the number of school playing fields sold off in England.
Labour claims an estimated 10,000 playing fields were disposed of between 1979 and 1997 when the Conservatives were in power, but according to the BBC's More or Less programme, "no one really knows the true figure because nobody counted".
Tom Harford explains.