Regarding the OSA, I worked for a local government dept, which was taken into the civil service. All staff received a generic email confirming our transfer of employment and stating that by dint of accepting the transfer, we were deemed to have signed the official secrets act. Not sure how binding that was, given we never actually saw a copy of the act, were never told what it covered, or actually signed anything! Not sure if it covers this revelation, but it became so hideously beaurocractic and formerly decent staff turned into monsters because of the policies, that I was glad to leave. Please would some of you still write to me in prison, if I get carted off to jail for revealing that?
BTW, it wasn't a high profile job, it was a humble office job which I then got paid less for than I had previously. I'm not bitter mind you....