Professor David Hopkins, who will speak today at the Specialist Schools and Academies Trust conference, stepped down as chief adviser on school standards earlier this year. He told a conference for new heads last week that he felt the white paper focused too little on teaching.

“The big row I had with colleagues was that if you are serious about system-wide reform, you have to invest in teacher quality rather than structural change,” he said.

Professor Hopkins told The TES he worried that the new self-governing trust schools could become more competitive and lead to greater social inequality.

But in his speech today he will stress that these problems are not inevitable if schools collaborate. “Independence for schools must mean independence from interference, not from each other,” he said.

Professor Hopkins, now at London university’s institute of education, said he was optimistic that schools would work together after overseeing research on 30 partnerships between successful and struggling schools. His findings suggest that the weaker schools show the sharpest improvements, but that lead schools also saw significantly improved exam results.

Examples include Invicta grammar, a girls’ school in Maidstone Kent, whose head of English has been helping to run the subject at nearby Valley Park school for two years. The proportion of boys at Valley Park getting a C or better in English language GCSE rose from 23 per cent in 2004 to 51 per cent this year, while at Invicta it went from 61 to 77 per cent.

At the new heads’ conference last week, delegates asked Ruth Kelly, the Education Secretary, why they should support other struggling schools without financial incentives. Ms Kelly replied heads would be attracted by the challenge and “because they care about the pupils in their area”.