The Department of Health is spending millions of pounds on public health campaigns without any evidence they actually work, an official report will conclude this week.

Derek Wanless, whose first study on the NHS paved the way for tax rises to fund the health service, delivers a follow-up report on Britain's gathering health crisis this Wednesday.

Mr Wanless singles out for particular criticism the provision of NHS clinics to help smokers quit. He points out that ministers have no evidence they are effective.

The report by Mr Wanless, a former banker who is now an adviser to Gordon Brown, will also rebuff Downing Street's plans for new "fat taxes" to curb obesity.

Although Mr Wanless says that soaring rates of lifestyle-related chronic disease could cost the NHS up to £30bn a year, he has drawn back from recommending new taxes on unhealthy foods. He believes the duties would widen the gap between rich and poor, with potentially detrimental effects on public health.

Instead, his report, Securing Good Health for the Whole Nation, urges ministers to establish a new independent body to monitor the nation's health. Such a body would provide much-needed information on the most effective ways of helping people improve their own health.

Public health issues have climbed up the political agenda in recent months, with most attention focused on a doubling in the rates of obesity in Britain.

The depth of concern in Downing Street was revealed last week in a leaked report from Tony Blair's strategy unit on potential "fiscal measures" to promote healthier eating. This suggested burgers, crisps and even butter and whole-fat milk could attract higher rates of VAT "to signal to society that nutritional content in food is important".

The leak has been met with irritation in the Treasury, where officials suspect it was authorised to pre-empt Mr Wanless's conclusions.

The 200-page report predicts there will be a huge economic cost unless all sections of society take responsibility for their health. At the same time, it warns the health gap between rich and poor could widen over the next 20 years.

A Department of Health spokesman said: "Mr Wanless's conclusions will be an important contribution to the public debate launched by John Reid into how the nation should tackle issues like obesity, smoking and sexually transmitted diseases."

A consultation on public health will be followed by proposed legislation in the coming months.