Warning: zoo animals could escape into park

In Regent's Park's 140 acres of greenery, visitors may spot a variety of animals: hedgehogs, foxes, grey squirrels, tawny owls, bats, damselflies and butterflies. And, perhaps, a tiger.

An unpublished inspection of London Zoo has warned that dangerous animals could quickly emerge into the outside world, after leaping an inadequate perimeter fence. That would lead to big cats surprising, not to say terrifying, the picnickers, joggers and tourists enjoying the adjoining park, central London's biggest.

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The warning came in an official inspection report by vets obtained by The Independent under Freedom of Information legislation. Their criticism is something of an embarrassment to the Zoological Society of London, which runs the oldest and most famous public menagerie in Britain. Although the zoo's tigers and lions are held in high security compounds, the Government-approved vets feared that if they did escape a 6ft perimeter fence would not hold them back for long.

In fact they would be able to climb the metal railings before marksmen fired their tranquilliser guns. Once out, the creatures would be faced with dodging traffic on the Outer Circle or roaming Regent's Park, a few miles from the West End and the Houses of Parliament.

The vets visited London Zoo for two days in January and warmly welcomed improvements for the animals, visitors and research. They singled out the zookeepers for praise.

But they warned: "It is a concern, however, that should there be a dangerous animal escape it is unlikely that the existing perimeter fence will contain a dangerous animal, like a tiger for example, for a reasonable period of time allowing the capture team to do their work."

The zoo, which is opening a new gorilla house on 30 March, acknowledged that the vets from Westminster Council had a point. But it assured the public that its enclosures were robust enough to prevent an escape in the first place. Its Sumatran tigers have an enclosure with a roof, while the Asian lions are surrounded by moat and a brick wall.

Zookeepers everywhere are trained to tranquillise or kill animals that escape. None the less, several animals have escaped or made a bid for freedom in Britain and abroad in recent years.

At Edinburgh Zoo last year three youths launched an unwise - and unsuccessful - attempt to smash the lock off the tiger pen.

In September 2005, a peccary, a pig-like animal with razor-sharp tusks, escaped from its home at Paignton Zoo in Devon, forcing members of the public to shelter in a building for 40 minutes before the animal was cornered in the elephant enclosure. Two months earlier, a Colobus monkey escaped from Belfast Zoo and took refuge in woodland before returning to its enclosure a week later.

In Berlin, three years ago, an Andean spectacled bear paddled across a moat and scaled a wall before attempting to commandeer a bicycle. It was shot with a tranquilliser dart.

In the same year a lioness got out of a rusty cage at Dhaka Zoo in Bangladesh. Zookeepers only noticed she was missing when they came to serve her breakfast. None of the escapes resulted in injury to people but David Field, London's zoological director, said the zoo was taking the criticism seriously.

"This was a comment by a very respected colleague and of course we will look into it," he said.

"Security is something we are constantly reviewing anyway. We will look into it and look at the feasibility of what is required."

London Zoo, founded in 1826, is small for a modern menagerie but Mr Field reassured the public a "Category A" gun crew was on stand by.

"We have minimised every possible chance of a dangerous animal escaping," he said.