The majority of packed lunches given to British school children were “disgraceful”, Oliver said, and he would like to see them banned.

The chef added that headteachers are too frightened of some parents to tell them what they should be giving their child to bring to school.

Oliver's criticism of parents comes in his new television show Jamie's Return to School Dinners, the sequel to his successful 4 series on improving school meals.

In the film Oliver said: “I’ve spent two years being PC about parents, now is the time to say ’if you’re giving your young children fizzy drinks you’re an a*******, you’re a t******. If you give them bags of crisps you’re an idiot. If you aren’t cooking them a hot meal, sort it out’. If they truly care they’ve got to take control.”

Oliver said after the screening of the new programme: “I have seen kids of the ages of four or five, the same age as mine, open their lunchbox and inside is a cold, half-eaten McDonald’s, multiple packets of crisps and a can of Red Bull."

The chef added: “I have no doubts that these parents love their children," but parents who think the solution to a tired child is a can of Red Bull, 'because it gives you wings' , might as well "give them a line of coke”, he said.

The chef describes himself as a lunchbox train-spotter. “There does need to be someone daddyish or mummyish at the top saying ‘they’re getting bigger, they’re getting fatter, they’re dropping dead younger’.

“Someone has to get strong, someone has to be the governor, and you don’t necessarily have to like them.”

Asked whether he would like to see a ban on packed lunches Oliver said: “Many of us would like to say yes, if there were facilities for better hot meals in all schools. I would love it but that will not happen.

“Packed lunches are a problem. Most of them, whatever anyone says, aren’t appropriate.”

Oliver would also like to see a ban on junk food advertising for children and in the new televsion show tells Tony Blair that a voluntary code sounds “a bit wet”. The Prime Minister promises Oliver an extra £240 million to improve school dinners for another three years. After a huge campaign sparked by the first series Mr Blair agreed to commit £280 million for proper ingredients and training. But £45 million of that. Oliver said, was based on a Lottery promise that hadn’t actually been signed off.

In the new programme, the chef goes to Lincolnshire, where kitchens were removed from schools to save money during the Thatcher years and where nearly 50,000 children take a packed lunch. Viewers see him attempt to reintroduce hot meals into the county by collaborating with local pubs and restaurants.

Oliver said he was “not saying parents are bad” but that the problem was they had not been taught how to provide their children with a healthy meal. Cookery lessons should be compulsory in schools, he said, not voluntary as the Government recently announced they would be.

“These young parents haven’t been taught from the family unit which is the best teacher," Oliver said. "There are two generations of young parents who don’t know how to cook ... It’s not normal, someone has got to say it’s not normal.”

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