Last month the Socialist Culture Minister, Carmen Alborch, announced that the civil war section of the National Historical Archive would be returned to Catalonia - and microfiches kept in Salamanca. The decision, taken by the ruling Socialists at the prompting of their Catalan partners in government, has unleashed a deafening row.
The fate of the civil war archives, which occupy nearly 3km of shelving, has blown up into a campaign issue for regional and local polls next month. It is now a hot element in the chemistry keeping the Catalan-backed Socialist government in power and the stuff of daily comment among ordinary Spaniards.
These are not dry old parish registers of interest only to historians. They are the personal records of anti-Franco fighters that were assembled and used by Franco to pick off his enemies in the orgy of repression following his victory in 1939.
"Franco stole these files and used them to keep tabs on and punish his opponents in Catalonia," says the English historian Andy Durgan, who teaches the civil war at the University of Barcelona. "They are not neutral."
Cambio 16 magazine described them last week as "a monument to police persecution". The Documents Recovery Service (SRD) was a special detachment that accompanied Franco's troops from 1937 onwards. As each town, city and village was captured, the SRD scooped up all the records of political parties, governments, the socialist, communist and anarchist trade unions, the Freemasons and fighters in the republican army, including the International Brigades, and took them to Franco's barracks in Salamanca.Historians say they have been working for years to turn these 507 boxes of police files into a respectable research centre, and that more than 70,000 republican fighters have used the files as a basis for obtaining (meagre) compensation for the persecution they suffered.
They say that to hand over the documents would strike a fatal blow to the archive's credibility and prompt other regions to make similar claims, eventually stripping their shelves bare.
The Basque country was swiftly on the case. "There exists a collection of original documents ransacked and expropriated from the Basque country," said a conservative Basque MP last week. The city of Valencia and the Pablo Iglesias foundation - the research arm of the ruling Socialist Party - also staked claims and the country's masonic lodges may soon take up a similar position. The Socialist mayor of Salamanca last month posted a 24-hour police guard on the doors of San Ambrosio to ward off anyone tempted to whisk away the papers in the night.
Last Wednesday, Ms Alborch said she would appoint a committee of experts to "reflect the scientific opinions that have been expressed". Some interpret this as a sign that the minister may be getting cold feet about the transfer. But the Prime Minister, Felipe Gonzalez, remains on the side of the Catalans.