Jay Altman, who leaves his post as education director of the academy sponsor ARK, said he has been “blown away” by English class prejudice. He also criticised new government limits to academy freedoms. He said the English and American school systems shared an “unintentional and largely unconscious” middle-class bias. But overt “classism” was much worse on this side of the Atlantic.

“I had someone working in a school say to me: ‘You don’t understand. They (pupils from deprived backgrounds) are a different breed’,” said Mr Altman, reflecting on nearly three years working with schools in deprived areas of London.

His comments came as a new book by Stephen Ball, from London University’s Institute of Education, argues that despite 20 years of “unprecedented government activity” English schools are returning to Victorian levels of class division.

Mr Altman has reached a similar conclusion. “A lot of people in this country believe that most working-class kids don’t have as much potential as more affluent ones. My retort would be there is enormous potential. It might be more challenging to unlock that potential, but we have also created a system that is ineffective at doing that.”

He cited the lack of training secondary teachers receive in basic numeracy and literacy tuition needed by many pupils in deprived areas. He also believes such pupils are more susceptible to problems caused by family breakdown and violent computer games.

Teachers, he said, are shying away from strict disciplinary structures that are a prerequisite for succeeding in more challenging schools. He disputes the idea that these can stifle creativity, pointing to the regime established by Sir Michael Wilshaw at the lauded Mossbourne Academy in Hackney, east London. Sir Michael takes over as ARK’s part-time education director next week when Mr Altman moves to the US.

On his return to New Orleans, he intends to open an “unprecedented” number of the charter schools he helped pioneer (he co-founded one 16 years ago that was destroyed by Hurricane Katrina). Charter schools are the US version of academies. They do not need sponsorship money and enjoy greater ‘independence.

Mr Altman said he was concerned that the academy scheme he has played such a major part in - ARK is a City-financed charity that has opened three academies and plans four more - is being compromised by the Government.

Asked about the recent move to require all new academies to follow the core national curriculum and encouragement of local authority academy sponsorship, Mr Altman said his initial reaction was: “Why?”

“Do these reforms allow people to search out more effective solutions to this problem of closing the achievement gap (between the most deprived and advantaged pupils)?” he said. “I don’t think so.”

But he believes England is moving towards wider success. “I have been bowled over by the commitment, work ethic and talent,” he said. “It has been an honour to work here.”

LESSONS FROM A SMALL ISLAND

Jay Altman’s recipe for closing the achievement gap

- Get the basics right first. Establish good behaviour, quality teaching and formative assessment.

- Less is more. Pupils from disadvantaged backgrounds will do better in small schools of no more than 300 pupils. ARK plans to eventually establish several within each of its academies.

- Be open to as many ideas as possible. A Government relying on a narrow spectrum of solutions has a much smaller chance of getting things right.