Rare breed of buildings under threat: A new book highlights the architectural heritage of the troubled London Zoo. Jonathan Glancey reports

'HOW MANY citizens of London have brooded over the railings of that pool, envying the penguins as they streak through the blue water or plod up the exquisite incline of the ramp - and have wondered sadly why human beings cannot be provided, like the penguins, with an environment so adapted to their needs?'

This was the response of the critic Malcolm Reading when first looking into the new Penguin Pool at London Zoo in Regent's Park designed by Tecton, the avant- garde modernist architectural practice led by the brilliant Russian emigre Bertold Lubetkin in 1934.

The Penguin Pool remains one of the zoo's greatest attractions. It was commissioned by the brilliant and eccentric Sir Peter Chalmers-Mitchell, secretary of the Zoological Society from 1902 to 1935, the man responsible for many of its finest buildings. Lubetkin told the story of how he went to lunch with Chalmers-Mitchell to discuss bringing modern architecture into the service of the zoo and being served python steaks. But, what buildings were born at that lunch: the Gorilla House, Penguin Pool and the Studio of Animal Art (the last demolished in 1967).

Today, as much concern is expressed over the future of London Zoo's unique collection of buildings as for its animals. If the zoo is transformed into an American-style wildlife theme park, its remarkable breed of buildings will become threatened and, ultimately, extinct.

Next week, the Royal Commission on the Historical Monuments of England publishes The Buildings of London Zoo (Peter Guillery, pounds 12.95), a fascinating study of the building of London Zoo and a record of the architecture that London stands to lose if the zoo should be put to the lions of Mammon.

The zoo opened in 1827 (the public was admitted from 1846) and its buildings represent more than 170 years' thinking as to how wild animals should be put on display. Was the zoo a scientific institution, or a pleasure park? Early buildings by Decimus Burton (architect of several of the white stucco Neo-Classical terraces surrounding Regent's Park) were exotic, but hardly kind to animals. None survive, at least not in their original form, although Burton's 'Tuscan Brahmin' bull house and Classical-Gothick elephant house would have made delightful tea- rooms today.

A later breed of Victorian animal houses, including the Reptile House (1849) and Insect House (1881) were strictly functional in design and inadequate only in terms of heating and lighting. Other Victorian displays such as the Monkey Pole and Bear Pit owed more to the circus than a zoological gardens and would be considered cruel today.

The real changes in thinking and design came with Chalmers-Mitchell from 1902; he commissioned such naturalistic enclosures as the Mappin Terraces (a clever miniature concrete mountain range dating from 1913), 'Pets' Corner' (1935, a place for city children to learn how to handle furry animals, and now the 'Childrens' Zoo') and the handsome Tecton pavilions of the 1930s.

The zoo stayed open throughout the Second World War and began building in free-range styles under Solly Zuckerman in the 1950s. Like his predecessor, Zuckerman encouraged imaginative design; the Elephant and Rhino Pavilion (a Brutalist pile by Casson Conder, 1962-65), the Northern Aviary (1962-64, by Tony Armstrong-Jones, Cedric Price and Frank Newby) and the underworld Charles Clore Pavilion for nocturnal mammals (Black, Bayes and Gibson, 1965-67) all date from Zuckerman's day.

Later enclosures such as the New Lion Terrace (1972-76, Toovey, Wears and Balkwill, with Margaret Maxwell as landscape gardener) have been much more naturalistic in their design, allowing the great cats room to leap as well as to prowl.

Seeing these noble beasts spring on to their resting platforms is a reminder that the animals in the zoo are not cuddly toys or even particular friends of man but wild beasts held in cages, pavilions and enclosures that at best can only be inadequate for their needs.

Yet, the story of the zoo's architecture - a history of how we have chosen to display wild animals - grips the imagination. When the zoo becomes a playpen for leisure-seeking, burger-chomping, gawking humans in their striped and candy-coloured shell-suit skins, these fascinating buildings will be confined to the history books along with the great auk, the dodo and the Euston Arch.

(Photograph omitted)