The biggest question raised by the forgeries in the National Archives is: how did they get there? Any member of the public carrying proof of identity, such as a driving licence, can access almost all of the archives in Kew, south-west London. But readers are subject to constant supervision by uniformed security guards and a host of CCTV cameras. However, most of the security is aimed at preventing documents being smuggled out, rather than in. The main obstacle to contaminating files is the difficulty of unpicking clumps of papers that might be several inches thick and held together by a Treasury tag at the top left corner. Guards would almost certainly see someone unpicking a file. But Dr Audrey Giles's forensic examination shows that none of the documents was properly fixed into its respective files. In each case, the punch-holes in the top left hand corner were torn through. In other words, it would have been possible for somebody to take the documents into the archives and slide their torn punch-holes around the string of the Treasury tags that hold such files together. An official investigation will look at who has had access to the previously secret documents. The file containing the Bracken letters was opened on Feb 4, 2002. Mr Allen came across the documents in autumn 2003, providing plenty of time for someone to insert the forged items. The Bracken file has been presented to readers on 21 occasions. | 
