Around one in eight schools do not have a library, with poorer children less likely to have access to one than their richer peers, according to a study.
Primaries are less likely to have a dedicated library space than secondary schools, and in many cases, libraries are being used as classrooms or meeting rooms rather than for their original purpose.
Campaigners are warning there is an “inequality of access and opportunity” that needs to be dealt with so all children can benefit from what a school library has to offer.
The study, based on a survey of 1,750 schools across England, Wales and Northern Ireland, found that 87% have access to a designated library space, meaning around one in eight (13%) do not.
A breakdown shows schools in England were most likely to have a library, at 90%, dropping to 67% in Wales and 57% in Northern Ireland.
The survey also shows discrepancies between rich and poor – 91% of schools that have between none and 9% of pupils eligible for free schools meals – a key measure of poverty – have a library area.
This drops to 81% among schools where 25% to 49% are eligible for free dinners, and to 56% where half or more pupils are eligible. Only 12 schools in this final category took part in the survey.
“These findings indicate that pupils in schools with a higher proportion of free school meals are less likely to experience the range of positive benefits a school library can provide,” the report said.
Research has shown the benefits include improving reading and writing skills, more enjoyment of reading and improving general academic achievement, the study added.
The vast majority of secondaries (96%) said they had a school library, compared with 85% of primaries.
More than half (59%) of school libraries were reported to be used as a classroom for non-library lessons, and a similar proportion (51%) were used for meetings.
A third of schools said pupils continued to have access to the library space while it was being used for an alternative purpose.
The survey was commissioned by the Great School Libraries campaign, a three-year project which aims to ensure all children have access to a decent school library
Nick Poole, chief executive of CILIP, a library and information association, said: “We welcome this landmark report as the first comprehensive picture of the state of play in our school libraries.
“On the one hand, it is a testament to the head teachers, teachers, governors and librarians that value and promote the importance of school libraries for learners and their school.
“On the other hand, the research paints a picture of inequality of access and opportunity and insecure employment that we cannot accept.
“The findings highlight the urgency of securing national school library strategies and investment in England, Wales and Northern Ireland, drawing on the example of Scotland.”
Shadow education secretary Angela Rayner said: “These figures show the consequences of cuts the Tories have imposed on our schools. Even worse, it is clear that the highest price is being paid by those who most need the extra help.”
A Department for Education spokeswoman said: “We want all children to have the opportunity to read widely – that’s why we’ve strengthened the national curriculum to focus on developing reading skills, and increased the focus on phonics to help children acquire the basic building blocks of reading.”
She added that the extra education funding recently announced will allow schools to invest more in teachers and resources, including libraries.