Free school meals are the key to tackle child obesity

A study by University College London predicted that obesity levels among children in England will increase "considerably" by 2015 unless action is taken to reverse the trend.

They calculated that around one in 10 will be obese by that date, with rates up to 50 per cent higher among children from lower poorer backgrounds.

"This highlights the need for public health action to reverse recent trends and narrow social inequalities in health," the authors argued.

And they targeted aggressive promotion of cheap junk foods and lack of access to a healthy diet and exercise as the main cause of rising childhood obesity.

Geoff Martin of pressure group Health Emergency accused ministers of "sacrificing children's health for ready cash" by selling off local playing fields in deprived inner city areas.