Obesity could overtake smoking as the biggest preventable cause of cancer in women.

Cancer Research UK has said that more must be done to raise awareness of the "huge public threat" posed by obesity.

If current trends continue obesity-related cancers in women could account for 23,000 cases by 2035, just 2,000 shy of the number which researchers said would be caused by smoking by that year.

By 2043 excess weight could cause more cancers in women in the UK than smoking, the charity's report concluded.

Authors acknowledged projections of cancer incidence beyond 2035 are less precise but said it could happen if current trends, showing the smoking-obesity gap narrowing, continue.

Any such takeover in male cancers is likely to happen much later, the report found, as smoking is currently estimated to cause almost twice as many cancers in men than excess weight.

The charity, which used a formula combining projections of cancer incidence, smoking prevalence and overweight and obesity prevalence, is now launching a UK-wide campaign to increase awareness that obesity is a cause of the disease.

Only around one in seven people in the UK are aware of the link between obesity and cancer, the organisation said, as it called for measures including a ban on junk food adverts before the 9pm watershed and for restrictions on price promotions of less healthy food and drinks.

Professor Linda Bauld, a prevention expert at the charity, said: "The decline in smoking is a cause for celebration. It shows how decades of effort to raise awareness about the health risks plus strong political action including taxation, removing tobacco marketing and a ban on smoking in indoor public places, have paid off.

"But, just as there is still more to do to support people to quit smoking, we also need to act now to halt the tide of weight-related cancers and ensure this projection never becomes a reality."

A spokesman for NHS England said: "Obesity is the new smoking, one of the greatest public health challenges of our generation, placing people at much greater risk of cancers, heart attacks and other killer conditions as well as Type 2 diabetes.

"Expanding waistlines also mean a heavier burden for taxpayers which is why, as we draw up a long term plan for the NHS, we are exploring all options to help patients to help themselves and help the NHS."