In my earliest years, the local exchange was Hainault, the last London exchange to be manually switched with operator connected calls. This had the benefit that the 3 minutes limit didn't exist on local* calls. When in 1965 the exchange was replaced with a normal automatic one, (as the 01-500-nnnn series), we all had to get used to the 3 minute limit. A few years later, I moved to Chelmsford and then Colchester, where 'a', 'b' & 'c' std rates became significant, calls were much more 'measured'!
* - For those not familiar with the phone network 60 years ago, London, (and to a lesser degree, the metropolitan areas of Birmingham, Edinburgh, Glasgow, Liverpool and Newcastle) so-called 'Director' exchange equipment meant local exchanges had a three figure number followed by a four figure line number. Calls within the greater director areas all incurred local charges, which in London's case could mean 20+ mile distances reduced drastically the number of expensive STD (Subscriber Trunk Dialled) calls.