I know that data security has been a hot potato with Government in the last year or so, but another asepct of security that needs to be remembered is that of physical access by security pass right? Of ocurse, security passes, even in the private sector, get lost, or might be stolen when they're in a wallet etc.
Interestingly, most of the departments that have responded to questions on this matter have not really lost that many, the Cabinet Office for example has only had to issue one replacement pass over the past few years. Meanwhile some other departments have reported ranges from 10 to about a 100.
That is with one exception, the Ministry of Defence. Since January this year they have recorded the loss or theft of 5,313 security passes. That's about 15 security passes a day lost or stolen in the department that really ought to be the most anally secure.