TalkTalk now have a system where, if the caller is not from a number in your call history, the call is diverted* and they have to introduce themselves by name, then your phone rings and you hear a recording of the caller saying their name and you press 1 if you'll accept the call.  Can't remember how you reject it

*When I started typing this I had the appropriate word in my head but have now lost it  "Inter-something"?  There's no hope for me