I last went to London Zoo in the early 1970s as a young child so my memory might be playing tricks ....... I really can't recall the exterior lion area at all (my clearest memories are of Guy, and the polar bears), but do have a recollection of eating lunch inside what I recall as a long Victorian corridor, one side of which had what could only be described as barred cages, which was the lion's inside area.
I could be totally wrong about this (maybe I have confused the zoo with scenes from films etc) and stand to be corrected ....................
From your description that would be the old Lion house. Built in the mid 1800's and demolished in the early 1970's. It consisited of many of these indoor cages aswell as outdoor enclosures - Looking like barred conservatorys with a concrete floor. Although known as the Lion House it housed many species of cats im sure i could find a picture somewhere of it.
It was the typical enclosure of its time but from pictures ive seen was good in space with the outdoor cages at the time they were added compared to other famous collections.
Regards
