The fate of school library services run by local authorities is in the balance.
Two or three could be forced to close every year if proposed changes in funding go ahead, the Library Association has warned.
In a report to the Department for Education and Employment, the association says the changes would put quality on a "downward spiral" and calls for school library services to become statutory.
The librarians' professional body hit out at Government moves to delegate more funding from local authorities to schools.
Changes would mean schools become responsible for spending on meals, staff, repairs and libraries.
The Library Association fears that membership of a library service would be one of the first sacrifices a school would make in a financial crisis.
"People may say yes there's choice involved, but when you've got a leaking roof and a big teachers' bill, then there isn't an awful lot of choice," said Anthony Tilke, the association's adviser for school libraries.
"Those authorities that have delegated their services have done marvellously. But there have been some casualties along the way - usually about one school library service per year goes.
"For a long while it has been our policy to make them statutory. In Northern Ireland they are statutory - now we are seeking parity. We'd like to see standard provision for every child and teacher to get that support."
School library services take advantage of economies of scale - holding a large stock of books and a range of learning resources centrally means they can be used time and time again in different schools.
Out of 121 school library services in 130 local authorities, 47 currently operate with schools using delegated money to buy into the service. The remainder are funded totally or partially by local authorities.
Since 1992 the number of pupils served by school library services in England has reduced from 93 to 82 per cent. The Library Association says a number of services have been forced to close, including Liverpool, Newcastle-upon-Tyne and Oxfordshire.
Levels of delegation and experiences of funding vary enormously throughout the country. And not all SLSs are opposed to delegation of funding.
In Buckinghamshire the school library service for primary and special schools has been totally funded by the local authority, but is now being hit by county council cuts.
The service's loan collection for the county's 200 primary schools is to stop and 12 staff are being redeployed in public libraries.
Mike Ryan, Buckinghamshire's primary and special schools librarian, said:
"I think that if the SLS budget had been delegated two or three years ago, that money would have been in schools and it would have been more difficult for councillors to delete that money.
"But as it was a centrally-held fund it was identified as being a non-statutory service, then I think it made us extremely vulnerable.
"I feel that if a service is delegated and properly delegated and well-researched and so forth, provided the schools are sufficiently funded that probably will put the school library service in a more secure position than say a service that's totally centrally funded.
"SLSs have developed because they're a good idea. And because librarians, education officers and teachers have put an enormous amount of time and effort into developing them. I think if they were to be lost, that would be a great shame."