Child obesity is costing more than �7 million a year to treat, the London Assembly warns today.

This annual bill for London could reach �111m if today’s youngsters remain obese into adulthood—with higher obesity rates than any other region, according to new figures.

Boris Johnson is trying to tackle fitness issues with projects like his famous rental ‘Boris bikes’ to get the population fit.

But few of his schemes are focused exclusively on reducing obesity and are not co-ordinated, the Assembly’s health committee has found.

Committee chair James Cleverly said: “Something must be done to stop today’s youngsters becoming obese adults. It’s a major problem that’s already costs London millions.”

One-in-five youngsters is obese, especially in deprived inner city areas like the East End where most junk-food takeaways are near schools.

But highest child obesity rate is Westminster, where more than a-quarter are seriously overweight.

The Assembly found ‘lifestyle’ counselling by GPs and ‘walking school bus’ programmes were failing, while most cost-effective were ‘multi-faceted’ programmes combining diet advice and physical activity.

It calls on the Mayor to set up a London strategy by 2013 to tackle the reasons why a child becomes dangerously overweight.