Almost two million infants will receive a free lunch from today under a new £1 billion scheme, amid ongoing concerns about its cost.
The major new initiative, first announced by Deputy Prime Minister and Lib Dem leader Nick Clegg last year, will see every five to seven-year-old at England's 16,500 primary schools eligible for free dinners.
Ministers have insisted that the move will save families up to £400 per year as well having health and education benefits for youngsters.
As the programme was launched, Mr Clegg vowed not to let critics "cloud" his goal of creating a level playing field for all children, adding that the scheme is "one of the most progressive changes to our school system for a long time".
His comments come just weeks after council leaders warned they still had concerns about the scheme, claiming that local authorities and schools are being forced to raid existing budgets to ensure that the scheme goes ahead.
"I've made it a personal priority to give all infant children free school meals so I'm delighted that we are seeing this being rolled out across the country from the start of this school year," Mr Clegg said.
"All the evidence, including the pilots in Durham and Newham, shows that free school meals will not only help ease the pressure on household budgets and encourage positive eating, but will also help improve concentration and raise educational performance."
Earlier this year, the policy sparked a coalition row over the expense, with former education secretary Michael Gove and schools minister David Laws insisting they were both behind the scheme.
A poll by the Local Government Association earlier this month suggested some authorities are facing a shortfall in the funding they need to ensure it can be delivered.
Government funding worth £150 million, in addition to the £1 billion to cover the cost of the scheme, was handed to councils to cover the cost of bringing facilities up to scratch.
The LGA's survey of 75 councils found that nearly half (47 per cent) said they had not received enough money to do the required work.