If your sample is drawn from the prison population then it's probably biased towards those who got a prison sentence. Which is an extreme end.
Class A possession is a gravity score 3 offence. Which would normally result in a charge but in exceptional circumstances for a first offender would be a caution. This, by the way, is one circumstance where you shouldn't go "no comment" in interview, you're only eligible for a caution if you confess.
Whilst drugs may not be the new alcohol use is high amongst both the young and middle aged, although not necessarily class A. If you work in what you consider a professional office, try asking your neighborhood policing team to come and do a drug swipe of the toilets - it may be illuminating.
In this particular case, I hope there has been no charge - if there has then we shouldn't be discussing it. Most people are entitled to privacy until charged. Somebody has leaked this story, and that person should be in trouble too.