Britain should be a “nanny state” about food to ensure children are healthy, according to Jamie Oliver.

The celebrity chef said the nation has come a long way, but diet-related diseases are still a major concern and healthy eating, especially for youngsters, is a public health issue.

Speaking on his annual Food Revolution Day, he made a fresh call for a 20 per cent tax on sugary drinks and warned that parents should find it uncomfortable that the UK is the unhealthiest country in Europe, with children likely to live a shorter life than their mothers and fathers.

As part of Food Revolution Day, Oliver is leading a campaign for all G20 nations – which include the UK – to make practical food education a compulsory part of the school curriculum.

A change.org petition warning that the world is facing a global obesity epidemic, with 42 million youngsters under five classed as overweight or obese, has already gathered more than 1.2 million signatures.

An impact can be made by ensuring children eat the right foods for breakfast and lunch during term time, he said, and it should also be easier for parents to choose decent food.

“I think there should be much more legislation on marketing of rubbish, junk food, much more incentives for fruit and veg – or veg and fruit, more importantly,” the TV chef said.

He said a tax on sugary drinks would raise around STG1 billion ($A1.94 billion) a year, which could be split between health and education.