Part of which was caused the very "antagonistic" IB or SD like the US postal Inspectors.

There was a bit guilty by suspicion tendency that went on and I suspect some of this culture was embedded in the organisation.

Certainly having yourself or your staff investigated by SD was considered very stressful even after the "bad old days"

BT = British Telecom. British telco, which used to be part of the government-owned Post Office, but was separated from it in 1981 and then privatised in 1984. The delivery services part of the Post Office (Royal Mail) was separately privatised in 2013; but the retail post office business (Post Office Ltd) remains under full government ownership, albeit most of the individual post offices are privately run by franchisees – and it was these franchisees who were being prosecuted

IB = Investigation Branch – https://www.postalmuseum.org/blog/the-post-office-investigat...

SD = Security Division