Jamie Oliver has warned it is "morally, socially and financially unacceptable" that children are becoming unhealthier as he attacked politicians for failing to tackle the problem.

The TV chef said he was making it his own personal goal to reduce childhood obesity in the UK by at least 5% in the next five years.

And he said he was "deeply offended" that none of the nation's politicians, regardless of party, had made the same pledge.

Oliver was speaking ahead of tomorrow's Food Revolution Day - an annual global event aimed at getting children interested in food and cooking as well as encouraging them to eat healthily.

"I know to some of you I'm like a broken record. You've heard me talking about food and its impact on the health of our nation for many years, but you've got to hand it to me, at least I'm consistent - I won't ever stop demanding positive change that gives the next generation a brighter future," he said.

"It's a sad fact that our children are getting unhealthier and they're expected to live shorter lives than their parents. This is morally, socially and financially unacceptable, which is exactly why this record will carry on playing."

In a message ahead of the event, Oliver said that decent family food does not need to be pretentious or expensive, but is about being aware of the option and knowing how to make the right choices to enjoy a varied healthy diet.

"I hear loads of cynics saying that I'll never be able to change anything," he said.

"T hey say that junk food marketing and the ready availability of fast food is just too powerful. But I'd say in response, screw you. I know that most people, if they're really honest, are fed up with the same old rubbish.

"People do want better for themselves, their kids and their communities, and this is why I've given myself a personal goal to try and reduce childhood obesity in the UK by at least 5% in the next five years.

"It deeply offends me that there isn't a single politician from any party in this country that has personally committed to the same challenge, and that the CEOs of every supermarket in this country haven't either."

The chef said that it is every child's human right to learn about food at school, and called on governments worldwide to make the subject a "fundamental must" in every school.

"Whether it's Britain, the US, Zambia, Australia or Sri Lanka, or any of the other 95 countries taking part (in food revolution day), they're all getting involved this year to shout about the need for food education in their countries."

Among the events taking place tomorrow is a bid for a Guinness World Record for the biggest ever cooking lesson.

Oliver said: "None of the changes that I want to happen in public health are rocket science - it's simply about families and communities having access to fresh, good ingredients and the knowledge to turn them into tasty, affordable meals.

"Food Revolution Day is about focusing on kids and their right to food education. There isn't one single solution that's going to fix our kids' health; it's a whole host of things. Whether it's schools rolling out the compulsory food education that's coming into play this September or the continued improvement of school food.

"Whether it's the food industry upping their game or supermarkets using their prominence to empower us, rather than just sell to us. Or whether it's governments protecting our children from junk food marketing campaigns or stopping the people who allow yet another army of fast food joints opening right on the doorsteps of our kids' schools.

"There is so much that needs to change and it will. The question is when. Will it be soon, or when it's too late? Will Britain lead the way or will we follow?"

A Department of Health spokeswoman said: "We are serious about tackling obesity and are already making progress. Through our National Child Measurement Programme, every child of primary school age is offered the chance to be weighed and measured, and our free NHS Health Checks also assess body mass index and offer advice and support.

"The rate of child obesity is levelling off, but we know we still have much further to go.

"We've given local authorities the power, freedom and protected funding to make sure they can tackle obesity in their local areas. However, everyone has a role to play to tackle obesity. The Change4Life campaign offers advice to families on how to improve their diet and lifestyle.

"We are working with industry to reduce fat, sugar and salt in foods to empower consumers to make healthier choices."

Barbara Harpham, national director of Heart Research UK said: "We're wholeheartedly behind Jamie. If children know about healthy food and choose to eat it the lesson is there for life, but children don't buy their own food, or put food in front of them, it's the people who look after them.

"Caring has to include what's on a plate so let's have family sessions to make it's everyone's responsibility."