In a disused industrial complex in the northern suburbs of Philadelphia lies one of the city's two KIPP (Knowledge Is Power Program) charter schools. Housed on the top two floors of a derelict building, principal Marc Mannella and his staff are transforming the lives of Philly's most disadvantaged children.
KIPP's results in Pennsylvania's standardised tests are well above the state's average and the value-added results are astounding.
Rachel Wolf, director of the New School Network in the UK, wrote on these pages recently using KIPP's success as a reason to establish similar schools in England "without red tape and central interference".
There will be few teachers and heads who wouldn't want less government meddling, but policy makers should be cautious about trying to transpose KIPP's triumphs into the British system.
I met Mr Mannella in July and he explained to me the thinking underpinning KIPP's success: teachers focus on data and results, the children arrive at 7.30am and leave at 5.30pm and the principal has the power to make decisions about staffing and budgeting.
These ideas are such a radical departure for American schools that the results gap is not surprising. The constraints on teachers in US publicly funded schools are much greater than in the UK; they are told by the local district authority which textbooks they must buy and principals have no say in whom they hire - they are simply allocated teachers by a central district pool.
To compound a teacher's misery, every school's behaviour policy is set by district staff, sat in downtown offices. As Ms Wolf remarked in her article, the two teachers who set up KIPP knew they could do better. They did so by granting their staff the freedoms that were devolved to British teachers a long time ago. As my day at KIPP progressed, it became apparent that I was simply witnessing an excellent primary school, similar to an outstanding British school.
While a British charter school movement would no doubt spawn exceptional schools, it would not offer the sort of achievement gains we see at KIPP; independence and lack of government interference alone will not alter the underlying causes of persistent academic failure in our poorest communities.
The factors influencing a child's attainment are more complex than eradicating bureaucracy and granting autonomy. The challenge to improve secondary education in the socially deprived areas of the UK is a challenge that begins 11 years before the children walk through the door and involves more people and establishments than the schools themselves.
KIPP's success puts it in a league of its own among US charter schools. Studies by the think-tank Research for Action has shown that pupil performance in most charter schools is no better than traditional schools, and in many cases worse. This suggests that a British charter school movement would create as many bad schools as good ones - a predicament not too dissimilar to the situation with state schools.
James Richardson is a researcher at the MNS Foundation and former Thouron Scholar at Pennsylvania University.