Media playback is unsupported on your device Media caption Shadow health secretary Andy Burnham: "I think the time has come for new thinking"

Labour has urged the government to consider introducing legal limits on sugar, salt and fat content in food.

Shadow health secretary Andy Burnham said current voluntary agreements with the food industry were not working and the obesity problem was worsening,

He said Labour will soon begin a consultation on how to tackle obesity.

The Department of Health in England said its Responsibility Deal with food companies shows the voluntary approach can be successful.

At its core this is an argument about how best to reduce levels of fat, sugar and salt in our food - through regulation, or collaboration.

The coalition says working with industry through the Responsibility Deal has improved food content and labelling.

But Mr Burnham said the "time has come for new thinking" and asked whether a legal limit on the amount of fat, sugar and salt, especially for foods aimed at children, should be established.

'Helpful to parents'

Labour's consultation paper Children, Food and Obesity says parents are primarily responsible for ensuring their children eat healthily, but it argues that government also has a crucial role.

If we don't meet our targets and continue to make the progress that we have to make, then we would consider legislation Jeremy Hunt MP, Health Secretary

Mr Burnham told the BBC: "This is a problem we can't carry on ignoring. It is storing up great problems for the NHS in the future.

"I think parents need more help to make healthier choices for their children, I include myself here.

"A lot of the time people don't realise just how high in fat, salt and sugar some of these products are, even when you're trying to make healthier choices.

"The industry needs to show more responsibility and come forward with products that are going to be helpful to parents in making the right choices," he concluded.

Recent NHS data has indicated that a third of children in England are either overweight or obese by the time they leave primary school, putting them at greater risk than ever before of developing serious problems such as diabetes and cancer.

The party says measures could include a 30% cap on sugar content in cereals aimed at children - significantly lower than in several well-known brands.

Mr Burnham denied Labour were promoting a "nanny state", insisting parents must "decide for themselves" on food choices for their children.

"I'm not talking about banning anything... my argument is, shouldn't we just bring down those fat, salt sugar levels to make them more healthier than they are?" he added.

Which foods should be regulated? Nutritionist Amanda Ursell highlighted five foods that she says could benefit from regulation: Breakfast cereals: to reduce high sugar content

Fruit juice drinks: these are drinks which are not pure fruit juice and can have added sugar - but are confusing to spot among pure fruit juice products

Ready meals: regulation would stop some brands adding too much salt

Crisps: caps could reduce salt levels

Biscuits, cookies and cakes: manufacturers might be encouraged to rethink levels of fat

The consultation will also consider tighter restrictions on marketing and improving access to healthy food.

Health Secretary Jeremy Hunt said the government was "making very good progress" in tackling childhood obesity, telling the BBC the Responsibility Deal has led to "significant reductions" in the salt, fat and sugar content of supermarket foods.

He added: "The reality is that supermarkets and the food manufacturers need to understand that we do reserve the right to legislate.

"This is not a problem we can just wish away. If we don't meet our targets and continue to make the progress that we have to make, then we would consider legislation.

"We have been able to deliver much faster results by going for voluntary agreements... but if we don't get that agreement, let's be absolutely clear, we will look at legislation. We are utterly determined to grip the problem," he insisted.

'Significant progress'

A spokesperson for the Department of Health in England added: "Our successes so far clearly demonstrate that the voluntary approach can work and we now have over 400 partners in the responsibility deal.

"We are working to reduce the amount of salt in food further, cut saturated fat consumption and we are exploring how to promote healthier food choices more widely. We also want more businesses making pledges so we get bigger results ."

Media playback is unsupported on your device Media caption Health Secretary Jeremy Hunt: ''This is a very serious problem''

The Food and Drink Federation also said collaboration between business and government had been a success.

"Through voluntary commitments, manufacturers have made significant progress in reducing salt, saturated fat and calories in their products. Salt levels have reduced 9% since 2006 and some manufacturers have introduced calorie caps in particular for snacks and soft drinks."

However, former regional director of public health, Professor Gabriel Scally, said the voluntary "collaboration" between food companies and the government was not working.

Speaking to the BBC he said: "I don't think anyone in this country actually thinks that the food industry are the right people to decide what we should be eating."

Professor Nick Finer, who co-authored a recent report on obesity by the Royal College of Physicians, said legislative measures had already worked in other European countries.

"In French schools food and drink is controlled and all marketing of foods high in fat, sugar and salt is banned unless they are taxed and marketed with a health warning.

"Studies have shown that following these measures, the number of overweight children in France has dropped from 18.1% in 2000 to 15.5% in 2007."

Nutritionist Amanda Ursell said introducing legal limits on food could be "incredibly useful" if it meant "manufacturers are encouraged to reformulate their products" and market in "a responsible way".

She said: "Children's food up to the age of one is closely regulated - so you know they won't have too much sugar, salt or fat. But at the age of one those regulations disappear.

"It's a slow process and the food industry has done quite well over the years, but this would be an extra incentive to go one stage further."