The British Library begins restoring online services after the hack

The British Library's main catalogue, which includes more than 36 million records, came back online on Monday after a cyberattack last year.

It is an important first step in the full restoration of services for those who use the UK's largest library.

But the catalog will only be available in “read-only” format.

Its chief executive warned that a full recovery for all services would be a gradual process, but said Monday was “a quietly good day, finally”.

The hack, which occurred on October 31, took the British Library's website down for nearly a month.

The Rhysida Ransomware group claimed to be behind the attack.

In November, the library confirmed that some employee data had been leaked.

The world-famous library contains one of the largest book collections in the world.

Its main catalog – which includes details of its printed and rare books, as well as journals, maps and sheet music – is of great interest to researchers around the world.

But since the hack, users have not been able to access it online.

Chief executive Sir Rowley Keating said the impact on researchers from around the world had been “terrible”.

Speaking on BBC Radio 4's PM programme, he apologized for the disruption to services.

Asked if he had considered paying a ransom to hackers, he said: “It is custom and good practice to never pay money to criminals, and as a large public institution with international standing it is easy to make that decision.”

He did not explain how the hackers gained access in the first place, but said lessons learned would be shared from around March onwards.

Sir Rowley said the main online catalog was back and available and searchable, as was the vast majority of the library's “completely unique materials” – books, archives and manuscripts.

In his previous blog post, Sir Rowley warned that the return of the main catalog will not work as well as before at this time.

While users will be able to search for items, checking for availability and requesting their use in reading rooms will be different.

From this week, readers will also be provided with access to most of the library's major special collections, including archives, manuscripts and other unique items but will have to attend in person to consult offline versions of the specialist catalogues.

“While processes may be slower and more manual than we are all accustomed to, this is the familiar heart of what the Library offers to researchers and restores an essential element of our public service,” he said.

“It would be nice to have him back.”

This will be followed by access to the range of content found on the Library's Boston Spa website as well as to parts of its digital collections that are not currently available.

Earlier this month, The Financial Times suggested The cost of rebuilding the British Library's digital services could reach £7m, but Sir Rowley said speculation about recovery costs was “premature”.