A morbidly obese 10-year-old schoolgirl weighs 22 stone 11lbs.
The unidentified Year 6 pupil was the most extreme case recorded of six similarly-aged pupils all weighing in at more than 19 stone, according to data revealing the scale of childhood obesity in Birmingham.
The figures, released to the Sunday Mercury, show that almost 50 children in the city weighed more than 16 stone by the age of 11.
The statistic were compiled by the Health and Social Care information centre, and obtained by a Freedom of Information request.
One quarter of year six children - typically aged 10 or 11 - are now classed as obese, while one in 10 children starting primary school are obese.
Birmingham City Council Cabinet Member for Health and Wellbeing, Councillor Steve Bedser, said: "The statistic of one in four 10-year-olds being obese is the single scariest thing I know about Birmingham.
"We took on responsibility for public health in April and it has been clear from day one that childhood obesity is an absolute priority in this city.
"This is a national crisis and failing to tackle the obesity time bomb is not an option. If the rising tide of childhood obesity is not reversed, the implications are stark for individuals, for neighbourhoods for families and for the public sector."
Almost 40 per cent of year six pupils were marked as overweight or obese, and 23.3 per cent of reception pupils were also classed in this category.
Dr Adrian Phillips, Director of Public Health for Birmingham, added: "Childhood obesity is far worse in Birmingham than the national average. It's a universal problem and a real emergency for the city.
"Obesity in children has now become so common that it is almost seen as the norm."
However, the overall numbers classed as obese fell in the area.
Dr Beckie Lang from the Association for the Study of Obesity said: "I am not shocked by these figures, in fact I am delighted that we are seeing a reduction in the rate of obesity in Birmingham for the first time in a long time. But there is no room for complacency.
"We have to hope that these children and their families of those who have these very high BMIs are getting the help and support that they need from the relevant health authorities."
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