The government has come under fire from educational software companies and websites over its plan to reserve £50m for web content for schools.

The Curriculum Online Scheme, launched today by Prime Minister Tony Blair, will be made available to schools in the form of "e-credits".

The credits will pay for online learning materials and teaching aids like those provided by commercial sites such as Learn.co.uk and SchoolsNet

However, educational publishers and websites are fearful the funding, which will only apply for one year, is merely a sop and the BBC will go on to establish a de facto monopoly on the Curriculum Online.

The BBC, they suggest, will soon submit its own application to the Department for Culture, Media and Sport to supply content to the Department of Education's learning portal.

It is estimated the BBC will spend up to £140m of licence-fee money on the plan over the next three years.

Those in the private sector claim they will effectively be frozen out of the market as most schools choose to get their content for free from the BBC.

"The BBC is steamrollering ahead," said one source.

"It has got away with it in other sectors because they were immature and splintered but established education publishers won't stand for it.

"Pushing to take on the whole of the private education sector is quite outrageous."

The BBC, critics suggest, will have significant influence over the content and management of the scheme.

It will develop most of the content itself and will own all such content, even where it commissions work from third parties.

Once developed, the management system and the content could be made available free of charge to schools, negating the need for schools to turn to the private sector.

However, it is not yet clear whether, if awarded the task, the BBC would charge for content or make it available for nothing.

"If that results in a reduction in the level of choice and a detailed prescription of the national curriculum being broadcast to all schools from a collusion of the BBC and the government, then that's bad news for everyone," said another senior source.

Other broadcasters, such as Granada and Channel 4, argue the content should be produced by a consortium of providers.

The BBC argues it should have the lead role.

Greg Hadfield, the chairman of SchoolsNet, which currently provides all its teaching resources and curriculum guides free of charge, said: "I welcome any new money for schools, if indeed it is more money and it is new.

"I have concerns, however, that the innovation and entrepreneurial spirit shown by SchoolsNet and other start-ups might be limited if the old dominant players such as the BBC and educational publishers muscle in."

Some publishers have indicated they will consider legal action if the BBC is awarded the franchise to develop the national curriculum portal.