Professor Tony Badger, Master of Clare College, has added his voice to concerns among academics that a dearth of resources may delay the release of a secret cache of 600,000 Foreign and Commonwealth Office documents.

Professor Badger, who was appointed in December as the independent reviewer overseeing the release of the so-called ‘Special Collection’, was responding to news over the weekend that lawyers representing a group of prominent British historians have written to Secretary of State William Hague, challenging the government to explain delays in transferring the previously inaccessible documents to the National Archives.

The letter delivered to Hague demands that the government sets out a clear programme for the public release of the collection. It warns that if work progresses at the same pace as that of the department’s 2011 declassification of documents from the colonial archive, it will be 340 years before the files are publically available.

The revelation that the FCO was in possession of such a significant number of non-inventoried files originally came about during a High Court case brought in the UK by four Kenyans concerning torture during the Mau Mau rebellion of 1952-60.

The government was forced to admit the existence of thousands of files concerning British colonial rule, which had been ‘migrated’ to the UK following decolonisation. This was in breach of the Public Records Act, which requires departments to make public their files after 20 years.

David Anderson, professor of African history at Warwick University, was a witness in the Kenyan case, having discovered the original memo revealing the existence of secret files. Today he is one of the leading voices putting pressure on the FCO for transparency.

Although he does not believe that the government has underhand motives in stalling, he bemoans the lack of procedural clarity: “We don’t know that there’s a lack of resources. They haven’t told us that. All we know is that they have 1.2 million files due for release that they haven’t released.

“For many years the Foreign Office has simply not been doing its legal duty. This material should not have been held without the Keeper of the Public Records knowing about it.”

Professor Badger said that he believes the slow pace of activity concerning the migrated archives is chiefly the product of a huge backlog of work within the FCO. Before documents can be released they must be analysed by experts to ascertain whether they were of any relevance for the National Archive, and redacted in cases where sensitive data is concerned.

He emphasised that the documents in question had not been accorded particular significance by FCO archivists prior to their public discovery, commenting that “the most remarkable thing about the migrated archive is that it wasn’t destroyed.”

Professor Badger does however acknowledged the understandable “legacy of suspicion” amongst his fellow historians: “[I]t is inevitable that there are suspicions because at one point there was a deliberate attempt to make sure not too many people knew about the migrated archive.”

Among the 10 per cent of the cache classified as ‘high priority’ are documents relating to compensation claims brought by British nationals who suffered Nazi persecution and records concerning the Cold War activities of Guy Burgess and Donald Maclean, part of the ‘Cambridge Five’ who spied for the Soviet Union.

Although the exact contents of the files remains a mystery, Professor Badger thinks it is unlikely that they will contain revelations of the same magnitude as the Mau Mau torture files. However, he added that it would include “great material for PhD students.”