Dilemma
With the "retained over a longer timeframe for historical, statistical or research purposes" element, when the government/civil service is asked if education and support of the disadvantaged in society are getting worse under their stewardship, they could be shown to not be doing a good job.
Without the data the opposition would claim that they are deliberately not keeping the data so they can't be exposed.
Can't win.
Biting the hand that feeds IT
