The report, by the National Child Measurement Programme, also found that almost one in three children in year six is overweight or obese.
The programme, which has been running since 2005, measured the weight of nearly one million children in England – 88 per cent of those eligible – of those in reception (aged four to five) and year six (aged 10-11).
London Strategic Health Authority has the highest percentage of obese children. In reception class children, 10.9 per cent were obese compared to the national average of 9.6 per cent. For year six children, 21.6 per cent were obese, compared to the national average of 18.3.
The report showed there was no significant change in the weight of England's children from last year.
Tim Straughan, the NHS Information Centre’s chief executive, said: ‘Obesity is one of the biggest threats to the health of our nation and it is of huge concern that the problem is afflicting so many children at such an early age.’