London's state schools have become one of education's biggest success stories, lauded by Ofsted, ministers and academics alike after recent results smashed national averages.
But as Boris Johnson this week launched a bid to further improve education standards, his team warned of a "culture of low expectations" in London schools.
A report commissioned by the Conservative mayor, published today, says that more needs to be done to ensure pupils achieve top grades, arguing that this cannot be left to London boroughs alone and setting out a blueprint for the mayor's involvement.
The suggestions in Going for Gold include an Excellence Fund, expected to be around #163;20 million over three years to help improve numeracy and literacy and science and technology subjects; more summer schools; a supplementary "London Curriculum"; and a scheme to address a shortage of school places by helping free school providers find sites.
To encourage "excellence", Mr Johnson is to establish a "Gold Club" of London schools, selected because they are "bucking the trend of low aspiration and underachievement".
"We need to stretch those in the middle and at the top," London's deputy mayor for education Munira Mirza writes in TES today. "Not enough attention is paid to helping young people achieve A*s and As.
"To get the much-needed C grades, schools have prioritised easier but less valuable courses. It is often children in disadvantaged areas that suffer from this culture of low expectations."
It is a markedly different emphasis from that of Sir Michael Wilshaw, Ofsted chief inspector, who last month held up London's schools as an example, writing: "The capital is now showing the way for the rest of the country."
Michael Gove has also praised London's "startling" results, attributing them to the London Challenge school improvement scheme, which ran in the capital between 2003 and 2011, and which the education secretary said inspired his own policies.
Tony Sewell, chair of the mayor's inquiry panel, acknowledged the success London Challenge had in helping schools meet floor targets, but said: "Today, headteachers in many London schools admit to struggling to get their students As and A*s."
In his foreword to the report, Dr Sewell - a former teacher who a runs a charity helping disadvantaged pupils get to university - writes about "a culture of excuses" and says there is no evidence that "the realities of economic and ethnic disadvantage" hold back pupils who are "driven by high expectations".
But Professor David Woods, who headed the London Challenge, said: "I am disappointed by the reference to 'low expectations' because the performance of London schools has demonstrated that it is the best performing region in the country. Schools in (more deprived) inner London alone are outstripping those in much more affluent shire counties."
Mr Johnson does not have any formal powers over education and his team say this is not an attempt to acquire any. The report also stresses this is not an attempt to recreate the Inner London Education Authority, which oversaw education in the inner boroughs between 1965 and 1990.
See Comment, pages 46-47
Boris Johnson's blueprint for London schools includes:
A London Schools Excellence Fund, which aims to improve literacy, numeracy, science, technology, engineering and maths standards; encourage innovation; and help teachers to develop practice and emphasise subject knowledge.
Encouraging schools to reduce exclusions and only use them as a last resort.
A London Curriculum, which aims to inspire secondaries to use the city to strengthen their curriculum. Mr Johnson's team are shocked that some London pupils have never read a Dickens novel or feel that St Paul's Cathedral is "alien" to them.
Measures to tackle a shortage of London school places, expected to reach 90,000 by 2015. The mayor will collect pan-London data to plan provision, identify potential free school sites and spread solutions such as more "through schools" and flexible buildings.