Wildlife programmes have made us much more aware of the natural world. This has prompted public revulsion against the squalid, imprisoning conditions in the world's zoos. Increasingly, people find it unacceptable to see lions and tigers pacing up and down tiny concrete cages.
London Zoo has responded to this concern for animal welfare with its showpiece Gorilla Kingdom, an enlarged enclosure. But this is still a tiny fraction of the territory that gorillas would roam over in the wild.
Moreover, it is not the gorillas' natural rainforest habitat. It is not forest at all. The open-plan layout is designed to put the gorillas on public display, so they can't hide away from the Zoo's cash-cows, the gawping, squawking visitors.
Other captive species are even more unlucky. Near the large aviary there are rows of small cages with two or three exotic birds in each. They have no space to fly at all. Camels, zebras and giraffes are confined in bare, barren enclosures – none big enough for them to be able to wander as they would in the wild.
Some smaller animals are isolated alone, or with only one companion. They are held in glass tiny display cases. The need for the public to be able to see the captive species takes precedence over the animal's welfare.
London Zoo's ultimate justification is conservation. But this is largely PR spin. The Born Free Foundation exposed the mostly poor conservation record of London Zoo and 12 others in the Consortium of Charitable Zoos. They house only 8 per cent of endangered mammals, just over 5 per cent of threatened birds, a mere 11 of the 1,811 at-risk amphibians and only 3.5 per cent of the species on the Red List of Threatened Species.
In 2007, Westminster City Council, which licenses London Zoo, admitted it had failed to undertake its duties "in relation to required inspections and implementation of conditions". This included neglecting to carry out annual inspections, and undertaking no inspections at all from 1995 to 2002.
London Zoo got away with no proper inspections for years. Why and how? The truth is, the Zoo should be closed down. It's unnatural, unkind and unfit.
Peter Tatchell is a patron of the Captive Animals Protection Society. He was speaking at Animal Aid's Christmas Fayre on Sunday.