The British Library has declined to store a large collection of Taliban-related documents because of concerns regarding terrorism laws.
The collection, related to the Afghan Taliban, includes official newspapers, maps and radio broadcasts.
Academics have criticised the decision saying it would be a valuable resource to understand the ongoing insurgency in Afghanistan.
The library said it feared it could be in breach of counter-terrorism laws.
It said it had been legally advised not to make the material accessible.
Alex Strick van Linschoten, an author and researcher who helped spearhead the project said it was "surprising and disappointing".
"There's no recipes for making bombs or anything like that," he said.
"These are documents that would help people understand history, whether it's Afghans trying to learn about their recent past, or outsiders wanting to understand the movement.
"Any scholar would realise it's essential to read primary documents related to your subject if you want to understand militant groups, but there is a climate of fear among academics who study this kind of material because UK law is very loose."
James Fitzgerald, a professor at Dublin City University and editor of the Critical Studies on Terrorism journal, said the library's decision was "completely, completely ridiculous".
He blamed the government saying its terrorism laws were making academics nervous about studying extremist groups.
"We're already seeing the effects. Some lecturers don't want to do modules on terrorism anymore because they don't want to come under suspicion."
The project, which was launched in 2012 and included members of the British Library on its advisory board, has digitised the material and translated it into English.
The British Library said it had been in discussion over whether to acquire and give access to the archive but it had been legally advised not to.
A spokeswoman said: "Although the archive was recognised as being of research value, it was judged that it contained some material which could contravene the Terrorism Act, and which would present restrictions on the Library's ability to provide access to the archive for researchers."
The Home Office declined to comment saying it was a matter for library.