20 years ago many European countries still had the PTT (where all communications services were owned by the government) and British Telecom still has close links with UK Government so they could (and often did) monitor anything they wish.
Often they didn’t bother with warrants at all, if a senior police officer could convince other staff at the PTT there was a genuine risk to society the info would be handed over. Attitudes to this of course varied within countries and even across regions but many folk genuinely thought drugs were a “plot from the Soviet Union”, a lot of European areas were (and maybe still are) highly religious and genuinely shocked by the sudden explosion in drugs culture across the continent (as it didn’t take too long before folk were ending up in the surgeries and hospitals from the after effects) and they were equally suspicious of the EU which was a new thing then and not fully implemented until 1999.
Many who grew up in during the 80s/90s simply assumed everything was monitored, fixed phones, mobile phones, radio communications, the Internet and took care what they said or posted.
You’d even get blatant hints dropped by the sort of profs posting to newsgroups like comp.sys.fortran with domains ending in *.mod.uk turning up on groups you wouldnt expect them to frequency, and posting that they were “working on certain projects” and they would often subtly tip folk off who might be veering across the boundaries between mischief and genuine criminality.
None of this stopped us having fun….
