When George W Bush left the White House in January, 140 terabytes of data – a terabyte being 1,000 gigabytes – were transferred to the National Archives. The electronic legacy of the Bush administration was 50 times larger than the data archive left by Bill Clinton just eight years earlier.

IT experts are confident that, at the end of Barack Obama’s administration, the archives will run to many petabytes (1,000 terabytes) of data. But dealing with mounting volumes of data storage is by no means a problem that is limited to governments.