Schools minister Lord Adonis has outlined the government’s plans to encourage independent schools to use state funding rather than raise money through fees.

A previously compulsory £2m sponsorship fee will be dropped in a bid to increase the roll-out of academies nationwide.

He also outlined general guidance for independent schools on sponsoring academies.

At present, up to 20 independent schools are said to have expressed a desire to move to join the state sector and around 250 schools will be targeted as potential sponsors.

Speaking to the Guardian, Lord Adonis said: "Successful independent schools will be exempt from the £2m sponsorship requirement when they set up or support an academy. It is their educational DNA we are seeking, not their fee income or their existing charitable endowments."

The move by the government to urge the switch from raising revenues through fees to being funded by the state sector follows on from such a move made last month by both the Belvedere School in Liverpool and William Hulme's Grammar in Manchester.

Richard Harman, headmaster of Uppingham School in Rutland which is one of the independents supporting academies, told the Telegraph: "We realised that we could help provide encouragement and advice to those considering sponsoring academies and to put them in touch with each other."

However, the government was rebuffed by Bernard Trafford, chairman of the Headmasters' and Headmistresses' Conference, who is in favour of independent schools retaining their independence.

"It is simply not acceptable to suggest that Ofsted should be both judge and jury – monitoring our inspections as it does now but also registering and regulating our schools," he said.

"So we must say very firmly - hands off. We are independent. We operate independently."