That sparks a memory of the uncommon sudden ubiquity in real ale in Courage pubs (certainly in the Bristol area) in the mid 70's.
There was strike of their mega-brewery or the distribution drivers, so the all-keg pubs had to turn to the local semi-autonomous George's (Courage) Bristol brewery for whatever supply they could provide.
Hence the heavenly appearance of George's BA poured by gravity from the small barrel on the bar (Pin or Firkin) wherever you came across a Courage pub when you needed one. A truly satisfying session lightweight bitter.
Shame when the 'normal service' kegfizz supply was resumed, but good while it lasted. Probably good for the overtime the George's workers obtained as well.
The cheapest I ever found it was 10 1/2p per pint in the Redland Teacher Training College student's bar. That seemed like the best beer that was worth drinking.