Downing Street has declared war on obesity with proposals for a fat tax on junk food.

Burgers, crisps, fizzy drinks, butter and whole milk will be hit under plans reported to be put forward by the prime minister's Strategy Unit.

Party Response: Liberal Democrats

Paul Burstow MP, Liberal Democrat shadow health secretary said: "Before reaching for the heavy club of taxation to tackle obesity, the government should be talking to the food industry about much clearer labelling of their products so that people can make informed judgments about how individual foods fit into a healthy diet.

"We all have personal responsibility for our own weight but that should not let the food industry off the hook. The industry must demonstrate that it is a willing partner in the fight against obesity."

Forum Response: British Retail Consortium

Richard Ali, director of food policy at the BRC, said: "We are deeply concerned that such proposals misunderstand the role of food in a healthy lifestyle.

"Health professionals and retailers work from the widely accepted principle that there are no good and bad foods, only good and bad diets.

"Indeed, government's Balance of Good Health promotes this fundamental truth. It is our belief that all policy should be firmly based on sound scientific evidence. Proponents of nutrient taxes therefore need to carefully consider the following questions:

"What foods would be taxed? Imposing taxes on certain foods may result in unhelpful consequences, such as dietary imbalance if nutrient dense foods such as milk & cheese were targeted. Do we really want to see calcium intake fall?

"What would be the tax? While its supporters wish to reduce consumer purchases of foods containing certain nutrients, influencing consumer behaviour through taxes is a complex area.

"Because nutrient taxes would bear no relationship to a person's income, they would be regressive and weigh more heavily on low-income consumers. Another tax on food would simply be another tax on consumers.

"Would nutrient taxes reduce overweight and obesity? Overweight and obesity result from an energy imbalance. Put simply, this involves eating too many calories and not getting enough physical activity.

"We believe that policy makers should focus their efforts on developing clear, consistent messages for the UK population, including a consumer education campaign to promote a balanced diet as part of a healthy lifestyle.

"Food retailers have been active in promoting healthier eating messages for many years. They stand ready to work in partnership to find innovative ways of playing their part in promoting this message and will continue to provide a wide range of well-labelled, convenient, attractive and accessible products, which allow their customers to opt for a healthier approach to food and drink. "

Forum Response: World Cancer Research Fund

A spokesperson for the World Cancer Research Fund told ePolitix.com: "The World Cancer Research Fund shares the concerns of the government and others about the growing obesity problem in the UK.

"Many people know of the link between obesity and heart disease and diabetes but fewer are aware of the link between obesity and cancer.

"Indeed, obesity is linked to some of the most common cancers, including those of the breast, bowel and prostate.

"It is estimated that in the European Union more than 70,000 new cases of cancer are attributable to overweight each year – and 9,000 of those cases are in the UK. After smoking, obesity is now regarded as the single largest avoidable cause of cancer in the UK.

"However tax incentives to encourage people to choose healthier diets would need to be done with care and must be based on good science, says the charity.

"For instance, an increase in the price of foods like burgers, that are high in saturated fats, might help prevent heart disease, but simply focusing on all fat might have little impact on both heart disease and obesity.

"The most important aspect of weight control is the amount of calories in food coupled with the level of physical activity undertaken by individuals.

"Some processed ‘lower fat’ foods are actually stacked high in calories because of added sugar that is used to compensate for the reduction in fat.

“One key message we need to get across to people is that low fat is not the same as low calorie and it is the calories they need to watch if they want to control their weight.”