The television chef Jamie Oliver has fiercely criticised parents who feed their children "junk", describing some youngsters' diets as a crime.
He said 70 per cent of packed lunches given to schoolchildren were "disgraceful" and he would like to see them banned.
Oliver said headteachers were too frightened of some parents to tell them what they should be giving their child to bring to school. He called on the Government to take the lead and give teachers the power to confiscate junk food at the school gates, because schools lacked the confidence to take such radical steps on their own.
He expressed disappointment at the Government's announcement this week that voluntary cookery lessons will be provided for secondary pupils arguing that only compulsory classes would be effective.
Oliver criticises parents in his new television show Jamie's Return to School Dinners, the follow-up to his successful Channel 4 series on improving school meals.
In the programme Oliver says: "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 arsehole, you're a tosser. 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."
Speaking after a preview screening of the new programme, Oliver said: "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. We laugh and then want to cry.
"I have no doubts that these parents love their children," he said. But he added that if a teacher told a parent that their child tended to get very tired at the end of the day, it was wrong to think the solution was "a can of Red Bull because it gives you wings - you might as well give them a line of coke".
He said it was a problem he had seen across the country in both rich and poor schools. Asked whether he would like to see a ban on packed lunches he said: "Many ofus 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."
He said: "Packed lunches are a problem. Most of them, whatever anyone says, aren't appropriate."
Oliver also called for a ban on junk food advertising for children and in the new programme tells Tony Blair that a voluntary code sounds "a bit wet". Mr Blair promises Oliver an extra £240m to improve school dinners for another three years and a package of measures which were announced earlier this week.
After a huge campaign sparked by the first series Mr Blair agreed to commit £280m for proper ingredients and training. But Oliver said he was "pissed off" because £45m of that was based on a Lottery promise that hadn't actually been signed off.
In Jamie's Return to School Dinners, he 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. The programme sees 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 healthy meals.
"These young parents haven't been taught from the family unit which is the best teacher. For whatever reason, be it work or whatever, they haven't done that."
Jamie's Return To School Dinners will be shown on Channel 4 on September 18