The proportion of children who attend free schools and are eligible for free meals is half the national average.
Freedom of Information requests sent to all 24 free schools revealed that 10 per cent of pupils could claim free lunches, which are available to pupils from low-income households. The national average is just less than 17 per cent.
The writer and free schools champion Toby Young said the discrepancy, revealed in figures published yesterday on the education blog SchoolDuggery, was because "[free] schools are perceived to be above average, and middle-class parents are generally more energetic about trying to secure the best possible opportunities for their children than parents on low incomes".
Earlier, Mr Young, who co-founded the West London Free School, accused the blog's author of lying: "This is utter balls," he wrote in a reply. "We haven't received an FOI request." He said a claim his school had no pupils with Special Educational Needs was "a flat-out lie", adding: "If you have to resort to these lies to discredit the free schools policy, you've lost the argument."
Mr Young later apologised after the blogger posted an email showing that the figures were real. He said: "I wasn't aware the school had received an FOI request... let alone replied to it, so I assumed [the blogger] must be making it up."