Hi Tiuchis,
Normally it's a minimum of 4 weeks from the final interview date. The security check generally takes that long to process. It also depends on the projected training schedule.
If you get an email shortly after the interview saying "THIS IS NOT AN OFFER OF EMPLOYMENT BUT from the list of dates provided what are your preferred start dates" - then you are pretty well assured your in (assuming of course you don't have something go wrong with the Security check or the medical pathology).
Having said that NOT receiving this email does not necessarily mean you didn't get the job!
Enjoy the wait!!
