Historians of empire have long suspected that documents from the colonies were transferred back to Britain during the last days of imperial rule, only never to enter into the public domain. It was no small surprise therefore when in April 2011 the Foreign and Commonwealth Office (FCO), under pressure from a high court judge, admitted that it had a secret archive of nearly 9,000 files from 37 colonies. Perhaps the biggest surprise from the ruling was how easy it was for the FCO to keep these documents hidden from historians for so long.
The FCO claims that it was simply unaware that these files existed. Historians, however, are sceptical of this claim. As David Anderson points out, it is easy for an archive to misplace one document or one file but it is harder to lose what amounts in the case of the ‘migrated’ colonial archive to over 100 linear feet of files.  Indeed, the subsequent ‘discovery’ of a further 1.2 million Foreign Office files held at the same site has only served to further undermine the FCO’s claim that it had misplaced or forgotten about the migrated archives.
It is also worth noting that the files were not being stored in some provincial archive, but at Hanslope Park, where the FCO ran its own parallel organisation to the Government Communication Headquarters (GCHQ). In other words, as Richard Drayton has suggested, these files were not simply kept for the sake of posterity but because their contents had what he describes as ‘operational value’ during the Cold War and would have informed Britain’s foreign and security policy. For example, the recently released Singapore files contain intelligence material on key political figures, such as future Prime Minister Lee Kuan Yew. Since this material was of strategic value, and given the FCO’s continuing reluctance to disclose the full extent of the files held at Hanslope Park, it is possible that further collections remain to be ‘discovered’ and that even the files that have been released have, in spite of claims to the contrary, been subject to some form of screening or vetting process. 
The discovery of these files and the process by which they have been released into the public domain raises some problematic issues for historians. It highlights the apparent ease with which government departments can withhold historical records and it demonstrates the difficulties historians can encounter when attempting to access such records.  Following the introduction of the Freedom of Information Act (FOI) in 2000 the FCO should have then disclosed the existence of the migrated archive and recorded all the items contained within it. This did not happen and it was only when judicial pressure was applied that the FCO admitted the archive had not been destroyed, as it once tried to claim, but had instead been misplaced. Yet, even when the existence of the archive became apparent, the FCO failed to produce a full inventory, with the result that FOI requests had to be made on a ‘case by case ‘fishing’’ basis’, further underlining the difficulty of obtaining access. 
The FCO’s apparent reluctance to comply with the terms of the FOI Act raises various other questions. Have other government departments withheld similar documents? And, if so, how can historians find out? These queries and revelations lead to an even larger question: how should historians now investigate and interpret the history of empire?
Of course, it is acknowledged that the content of any archive is shaped by the depositors and the archivists, and no historian would claim that an archive contains a wholly accurate or complete record of the past, particularly with regard to the history of empire, where the voices of colonial subjects are often absent from the official record. At the same time, however, it is hoped that by retracing the archival trail historians can at least understand how imperial policy was conceived and implemented.
Yet, the realisation that officials have been able to shape the archival record in a more profound and significant way than previously thought raises the possibility – providing that new and relevant material is released – that some events in Britain’s imperial past will need revisiting.  The migrated archives have shed new light on British counterinsurgency methods in Kenya, but other infamous episodes from the period of decolonisation are conspicuous by their absence. Who knows whether there is more material to be discovered on the Suez Crisis, for instance, or on the overthrow of Cheddi Jagan’s government in British Guiana? 
Beyond the need to possibly revise our understanding of the end of empire, there are broader implications for the way in which we think about how and why records are preserved. The FCO’s secrecy has been motivated in part by a desire to prevent details emerging that might embarrass or damage the reputation of Britain, namely information relating to the abuse of colonial subjects. As Drayton argues, this is tantamount to ‘historical narcissism, a desire for a Whiggish gaze into an unblemished
national past that leads to our time.’  It is also ironic since the FCO’s obstructionism is not only embarrassing and damaging to the state’s reputation, but is also an indicator of its culpability, or at least complicity, in attempts to cover up some of the darkest episodes in the history of the empire. Therefore, while granting that some secrecy in government is necessary, there can be no reasonable justification for withholding government records that are more than 50 years old. To do otherwise would set a dangerous precedent, allowing government officials to act in the knowledge that their actions might not be subject to future scrutiny.  The recent revelation that in 1949 senior British officials retrospectively introduced a ‘license to kill law’ in an attempt to legalise the killing of 24 Malaysian villagers in the Batang Kali massacre and that in the 1990s a Malaysian police inquiry into the atrocity was suspended following FCO intervention underscores the importance of this point.
Some historians have expressed disappointment at the content of the migrated archives, noting that the material released by the FCO contains information that is already known or is of little historical significance. The Aden material, for example, appears to be heavy on fishing and tourism but light on torture and detention.  In the case of Kenya, however, David Anderson and his team of Oxford history graduate students have found new material, some of which corroborates oral history accounts collected by other historians. In particular, the Kenyan files have revealed how officials at every level government discussed the issue of coercive force, its legal limits, and the abuse of such limits by both British and Kenyan soldiers. 
In addition, the fact that colonial administrations, and later the FCO, went to such lengths to burn, transfer, and then deny the existence of so many documents is in itself revealing. The very act of burning and transferring the files, a process documented in the latest tranche of documents to be released, was not an afterthought or some last desperate act before the few remaining colonial officials caught the last chopper out of Nairobi or Kuala Lumpur. Rather, it was part of the official process of decolonisation.
Specific instructions were issued to colonial administrations regarding how sensitive material should be treated and in some cases the process of destruction began well in advance of the formal transfer of power. In Aden, for example, officials began burning documents 12 months prior to independence.  The content of these files will never be recovered but the files documenting this process are illustrative of a hitherto unstudied aspect of decolonisation, while the content of the migrated archives is indicative of the type of material that officials considered sensitive, embarrassing, and of potential use to future policymakers. For historians this also reveals the objectives and fears of officials — dare I say the ‘official mind’ — amidst the uncertainty of decolonisation.
In sum, the migrated archives were always unlikely to contain the ‘silver bullet’ that historians had hoped for, but they are crucial for the study of empire and decolonisation in three key ways.
Firstly, it has helped to confirm or add to historians’ understanding of some of the key events during the period of decolonisation. Over the coming years, as historians continue to sift through this material our understanding of these events will undoubtedly continue to evolve and improve.
Secondly, the migrated archives are in themselves an important part of the decolonisation story, revealing another aspect of how British policymakers sought to manage the withdrawal from empire by controlling access to material that was both potentially embarrassing and of strategic value.
Thirdly, the migrated archives have helped to further challenge the myth that British decolonisation was somehow more orderly than that of its European counterparts. In turn, this has helped to validate the claims of victims who suffered abuse during the counterinsurgency campaign in Kenya, forcing the U.K. government to offer both compensation and an ‘expression of regret’. Other cases from other parts of the Empire are now likely to follow and historians must continue to pressure the FCO lest any remaining archives await ‘discovery’: or, even worse, destruction.
 David Anderson, ‘Mau Mau in the High Court and the ‘Lost’ British Empire Archives: Colonial Conspiracy or Bureaucratic Bungle?’, Journal of Imperial and Commonwealth History, Vol. 39, No 5. (2011), p. 708.
 Richard Drayton, ‘Britain’s Secret Archive of Decolonisation’, History of the Present, 29 April 2012, [online] http://www.historyworkshop.org.uk/britains-secret-archive-of-decolonisation/, accessed 3 December 2013.
 Anderson, ‘Mau Mau in the High Court’, p. 713.
 Drayton, ‘Britain’s Secret Archive’.
 Richard Drayton, ‘The Foreign Office secretly hoarded 1.2m files. It’s historical narcissism,’ The Guardian, 27 October 2013, [online], http://www.theguardian.com/commentisfree/2013/oct/27/uk-foreign-office-secret-files, accessed 3 December 2013.
 Drayton, ‘Britain’s Secret Archive’.
 Drayton, ‘The Foreign Office’.
 Drayton, ‘Britain’s Secret Archive’.
 Anderson, ‘Mau Mau in the High Court’, p. 710.
 Ian Cobain, Revealed: the bonfire of papers at the end of Empire, The Guardian, 29 November 2013, [online], http://www.theguardian.com/uk-news/2013/nov/29/revealed-bonfire-papers-empire, accessed 3 December 2013.