Columba House in Edinburgh, which houses the archives, has closed its doors indefinitely because there is no-one left to look after the service.
Curator, Andrew Nicholl, has been absent on long-term sick leave – which The Herald understands is due to the stress of the current shake-up of the archives. Just days ago, his assistant was told by the Church to leave immediately rather than work out a month's notice after she submitted her resignation.
Her departure left the archives unmanned, and researchers who had made appointments to view documents were given just 24 hours' notice that the service was being closed.
It comes amid controversial moves to uproot the archives – which contain more than a million documents dating back 800 years, including letters from Mary Queen of Scots and papers relating to Oscar Wilde – from their home in Edinburgh and distribute them to various locations across Scotland.
Professor Tom Devine, Scotland's most prominent historian, said: "Whatever the merit of the decision to disperse the Scottish Catholic Archives – and they are few to the point of invisibility –- this development is the latest in a long line of mismanagement and indifference to the interests of those who use the archives, and now to the loyal staff.
"Last weekend, at the University of Edinburgh, there was an international conference on Britain and the World, attracting 200 delegates from more than 30 countries.
"Some of these scholars were looking forward to working at the SCA during their brief stay in Scotland. This opportunity has now been lost."
Edinburgh University historian Dr Jenny Wormald, who led the campaign against moving the archives, said it was the worst possible timing as academics beginning their summer break would now have no access to materials for research.
She said: "Sadly, it is yet another example – of which we have had all too many as the argument over the future of the archives continues – where the last people to be considered are the scholars who use the archives to advance understanding of our Catholic, national and international history."
The archives were first centralised by bishops in 1958 to encourage research.
However, part of the collection known as the Blairs Library – 27,000 books from the pre-1878 era, which has been housed at the National Library of Scotland since 1978 – is to be gifted to Aberdeen University, where the head of the Catholic Church in Scotland, Archbishop Mario Conti, is an honorary professor.
The remaining post-1878 material at Columba House was originally destined for a renovated monastery in Pollokshields, Glasgow, but the plan was abandoned when dry rot and asbestos was found in the building. It will now be divided between eight separate dioceses instead.
The Church said it could no longer underwrite the £150,000 cost of keeping the archives open and free after funding from a private trust was suspended.
Dr Michael Turnbull, a writer of Scottish history and culture, said: "The archive was spread all over the country before and it was centralised for a reason.
"Now the clock is being turned back and the archive will be split not only into two parts – but the newer material dispersed across eight dioceses. It will be shoved in dusty cubby-holes with part-time staff and people are not going to be bothered with academics turning up at their doors."