I do disagree as far as architecture and cultural heritage is concerned: both buildings are 20th century only, a far cry from the early zoo development at Regent's Park. It is a question of political and bureacracy will under law venture. It then needs
public investment and in large quantaties (as it serves the zoo visiting public and the people of GLC and beyond).
The history of the Mappin Terraces structures goes back to 1913 architecture with the underground Aquarium built in 1921, so basically was a pre-+post-WWI
New Century building. Now the Casson Pavillion - was built in 1961-1962 and essentially part of the
New Zoo building period.
They would get slapped into the stratosphere with fines and all. Whereas I remain a firm supporter of cultural heritage in zoos in tasteful form for goodness sakes' if a building is no longer fit for purpose, is falling by the wayside, in danger of becoming a public health hazard or otherwise does not serve the needs of zoo animals nor animal welfare of any kind whatsoever ... than the arguments for cultural heritage become rather thin on the ground. If and when one wishes to preserve it provides an opportunity for access to national funds for cultural heritage to make it again fit for purpose and animal welfare. If not, at least the Casson bulldoze it and even the Mappins for all their former glory ... it has become an eyesore on the park and zoo grounds.
SOURCE:
Architecture at ZSL London Zoo, Regent's Park