. . . much as I love Bristol, I can't understand why it's suggested as a model. London has bigger collections of megafauna, small mammals, birds, herps, fish (for now), and invertebrates. It contributes vastly more to conservation and research, and exhibit quality is arguably higher. What is there to emulate?
There are parallels between London and Bristol and there are differences.
Both have relatively small city centre sites, with associated rural sites in the same region. Both have problems with "iconic" listed buildings and with other old buildings which have become unfit for purpose. They even have very similar lists of 'star' species to attract visitors including Indian lions, gorillas, pygmy hippos, aye-ayes etc.
Of course London has a larger site and consequently has more species, more visitors and bigger problems too. Being in the capital city certainly brings higher costs and a great deal more media attention and publicity - both good and bad: on the other hand, I would suggest that this makes it easier to attract funding from bodies like the National Heritage Lottery Fund.
I have visited both zoos many times since 1971, including visits to both within the last month, so I feel well qualified to say that there are several ways that London could emulate Bristol.
a) Listed buildings: there are three Grade II listed buildings at Bristol Zoo, the two entrance buildings and what was the Giraffe House. The South Entrance is now closed, but the architecture is preserved. The Main Entrance has been modernised and extended inside the zoo, but the external facade is unchanged. The Giraffe House was modified when an extension was built for elephants (in the 1960s I think) and again when the gorillas moved in and the last elephant went across the house and then being replaced by okapis. In 2012 the interior was imaginatively reconstructed to provide more space for the gorillas, without altering the external structure. Surely the Casson elephant house and the Mappins are prime candidates for similarly radical internal adaptations: imagine the interior of the elephant house hollowed out and spanned by a walkway over a manatee pool; imagine the whole inner section of the Mappins changed into a shallow slope for a herd of antelope, leaving the four artificial mountains as the skyline: of course such projects would need careful negotiations with Historic England and a good deal of capital, but Bristol's experience shows that neither of these are impossible.
b) Modifying older buildings: the conversion of Bristol's old bear pit into an Aquarium is another example of using an existing space imaginatively. The result may not be absolutely ideal, I have never liked the walk-though central tank, but the other exhibits are very good. I also like Bug World, where a range of good exhibits have been fitted into an awkward space - B.U.G.S may be a nicer building, but the exhibit quality is weaker in my opinion. The conversion of the Sobell Pavilions into Gorilla Kingdom doesn't seem to work well for either the gorillas or the visitors and the other species seem to be random leftovers. It is only fair to add that both zoos still have spaces that could benefit from renewal, such as the North Bank at London and the interior of Forest of Birds and Smarty Plants at Bristol (I do hope they demolish the old Monkey Temple before some fool suggests listing it too). Let us hope that the work goes well at Zona Brasil and the Snowdon Aviary.
c) Use of space: both sites have limited space, but virtually all the space at Bristol is used and cared for: the latest development being the conversion of a small area beside the giant tortoise paddock into an Asian Turtle Breeding Room. ZooChatters might think that too much space is devoted to play areas, gardens and lawns, but they all seem to be well used and appreciated by visitors. I understand that London needs trees and shrubs to screen parts of the zoo from the Outer Circle and Regent's Park, indeed some spaces like the steep canal banks can only be used like this, but there are lots of small areas between existing exhibits that appear to be unused and unloved. London Zoo seems to have lost interest in planning and building new small exhibits, and even in looking after the ones they have. The outdoor enclosures at the Round House end of the Clore are overgrown, so is the Komodo dragon outdoor exhibit, and the windowed exhibit in the south wall of the Reptile House is boarded up. Am I being unfair in wondering why more care seems to have been taken in arranging the display of flip-flops at the fake shoe stall in Land of the Lions than in designing and maintaining the neighbouring mongoose exhibit?