Almost a third of all adults in the West Midlands are obese, but for child obesity London and the north-east are worst, it was revealed today.

The figures were released by the Department of Health to help councils and NHS trusts in England develop strategies to tackle the problem.

Nationally 24% of men and women are obese and almost two-thirds (62%) are either overweight or obese. Related health problems cost the NHS £4.2bn in treatment in 2007.

However, local figures show pockets where obesity is even more prevalent. They show:

• In the West Midlands 29% of women and men are obese, compared with 19% of women and 21% of men in London.

• The number of morbidly obese women is also higher in the West Midlands at 4%, compared to 2.7% nationally.

• And if people who are overweight are added in, more than three-quarters (76%) of men in the West Midlands and 62% of women are affected.

• London has the lowest number of obese and overweight men (61%) and women (49%).

• But more than a third of children are overweight or obese in London (36%) and the north-east (37%). Yorkshire and the Humber has the lowest rate at 26%.

The figures are set out in a report, Healthy Weight, Healthy Lives: A Toolkit for Developing Local Strategies (pdf).

It aims to encourage PCTs and councils to tackle bad diet and lack of exercise which fuel obesity.

Then report says priority should be given to helping families with children under 11.

And it warns if action is not taken the cost to local PCTS could soar. For instance, Leeds PCT is estimated to spend £197m treating diseases linked to being obese or overweight, but by 2015 the cost could be £219m.

The chief medical officer, Sir Liam Donaldson, said obesity was serious threat to the country's future health.

"The link between obesity and preventable illnesses, such as diabetes, heart disease and cancer is undeniable," he said.

The government is to launch a public health campaign this autumn, Change4Life, to promote healthy living. A major publicity campaign is planned for next January.

Research for the campaign found only one in 10 parents with overweight or obese children recognised they had a problem.

The public health minister, Dawn Primarolo, said: "Obesity is the biggest health challenge we face - every year 9,000 people die prematurely. And many people simply just don't know that being overweight can lead to major health problems including heart disease and cancer.

"The Change4Life campaign will help us all to change the way we eat, the way we exercise and the way we raise our children so we can prevent obesity and related diseases."