One in three secondary schools has cut their library budget in the last year, a new survey has discovered.
These findings add to concerns about the future of school libraries as budgets get squeezed and more emphasis is placed on ICT.
The survey of 1,547 state and independent secondary schools by the Chartered Institute of Library and Information Professionals (Cilip) also identified a growing gap between the best school libraries and the rest.
David Streatfield, one of the authors of the report, told a reception at the House of Commons last week that the survey pointed to real problems.
"What is particularly worrying is that the cuts were being dished out to schools which had smaller budgets in the first place," he said.
"More than a quarter of libraries operate an extended school day, but more than a quarter are not open throughout the hours the school is open. There are quite token library arrangements in some places."
The survey, carried out in the spring term, found that among librarians with less than #163;1,000 to spend on stock and resources, only seven per cent got more cash in 200910 than in the previous year, while 30 per cent of those with more then #163;20,000 in the budget saw a rise.
Cilip also asked 651 primary schools about their provision. It found that more than half had seen their budgets frozen since last year and 18 per cent had received a cut.
About four in five primaries surveyed had a library space, 30 per cent had a school librarian - although they were not necessarily qualified - and one in seven libraries was not supervised.
The report was prompted by a question by Nick Gibb, now schools minister, in the House of Commons last year when he asked how many schools did not have a permanent library - and discovered there were no up-to-date figures.
Sue Shaper, co-author of the report and director of library resources at Broxbourne School, Hertfordshire, said: "People were shocked the government had no answer to that question. Alan Gibbons' Campaign for the Book was also bringing in a lot of hearsay evidence. We wanted more scientific meat on those bones."
The Campaign for the Book, headed by author Alan Gibbons, has now called for a moratorium on school library closures. Mr Gibbons said: "Are our reading standards really so high that we can allow these vital professionals and their libraries to vanish from our schools?"
A commission to look into the future of school libraries has been set up by the National Literacy Trust and the Museums, Libraries and Archives Council.
Chaired by Baroness Estelle Morris, it will report in September.
Why it can pay to play it by the book
When a YouTube trailer for the latest Time Riders book by Alex Scarrow was shown at Forest Hill School, a boys' comprehensive in Lewisham, the library was inundated with orders.
The trailer was the idea of librarian Carol Webb (below), who has helped raise literacy standards across the school through various activities including competitions, author visits and involving students in reviewing pre-proof copies of books.
"We had 40 copies in school and showed the trailer in assembly at 9am," she said. "By 3pm we had 147 orders and the publisher biked over more pre-proof copies."
Deputy head Mick Levens said: "We can show that having that resource raises literacy standards. Ms Webb runs an outstanding library which has the equivalent effect of a whole quality department."
The school's philosophy is that any student who can't do something heads for the library where someone will support them.
18% - Percentage of primary library budgets cut over the past year.