Bristol Zoo Gardens claims to have had the first ever nocturnal house, which opened in 1954. That said, it wouldn't last long, and in the time between then and the zoo's unfortunate closure they had three different nocturnal houses, the most recent and largest of these was known as Twilight World, and was originally intended as an Ape House, but was repurposed, and very well in my opinion. I believe the original has long-since been demolished.
Bristol isn't the only UK zoo to claim to have invented the concept, although they are the only ones who can back that claim up. A 1966 London Zoo guidebook of mine proudly boasts about the Bushbaby Hall (1963), an exhibit in the corner of the Children's Zoo, claiming that it was experimental and the only place where one has the opportunity to observe animals in such a setting. As well as the namesake bushbabies, there were lorises, pottos and other unspecified creatures, so it was very much a nocturnal house. Its greatest claim to fame is probably its magnificent breeding record with aardvarks, breeding them seven times in the eighties, a time where very few zoos had managed to breed the species who proved notoriously problematic.
However, the Bushbaby Hall didn't last long, and I have heard some say (although not sure if this is true) that it wasn't meant to, and rather it was a test of the concept, both of how effective and how popular it was, as in 1967, the zoo unveiled the Clore Pavilion. A building entirely devoted to small mammals, which at one point held more mammal species there alone than any other British zoo had in their entire grounds - the lower floor of it was a nocturnal house, named 'Moonlight World.' And, although the Clore is (in terms of animal numbers) a shadow of its former self, it still stands today, and the lower floor is still a nocturnal house, albeit now known as 'Night Life' instead. Therefore, at 57 years old, even though it isn't the oldest nocturnal house in the world, it is quite possibly (happy to be proven wrong here) the oldest still standing in the world.
However, while Bristol were the first to act upon it, they weren't the first to come up with the idea of a reverse-light setup. Wrocław Zoo intended to build one in the forties, but they never got round to it, according to guidebooks from the time (which I do not own myself, so this information comes from other ZooChat members).
