The escape of a large silverback gorilla from its enclosure at London Zoo “could have ended very differently” and must be subject to an urgent inquiry, a leading wildlife group has said.
The Born Free Foundation said the incident was a “startling reminder” of the risks of keeping dangerous wild animals in captivity.
Visitors to the popular attraction described fearing for their safety as they were ordered to take cover in buildings when the 29st dominant male ape got out of its den on Thursday evening.
Armed police were deployed at the central London zoo as keepers desperately tried to locate the animal, described by witnesses as “agitated”, which was eventually tranquillised and returned to its enclosure.
A zoo official said members of the public were “never in any danger” as the western lowland gorilla, called Kumbuka, had remained in a secure keeper area.
An investigation has been launched into the “minor incident”, they added.
However the Born Free Foundation has called for an inquiry and for the Zoos Expert Committee, the Government advisory body, to investigate the safety and welfare of great apes in UK zoos.
Chris Draper, associate director for animal welfare and care at the foundation, said: “While we are relieved that this incident apparently ended without injury to visitors or to the gorilla, it is yet another startling reminder of the risks associated with maintaining dangerous wild animals in captivity.
“This incident could have ended very differently. We are calling for an urgent inquiry into the circumstances surrounding this escape, and into safety procedures at London Zoo.”
The Born Free Foundation, which campaigns for zoos to be phased out, called on the Government to increase penalties for attractions if they are found to have put visitors or animals at risk.
There were no reports of injuries in Thursday’s incident and Kumbuka was later seen “up and grumbling and interacting with the rest of his gorilla family”, said Malcolm Fitzpatrick, curator of mammals at the zoo.
“Kumbuka got out of his enclosure and into a secure keeper area at 5.15pm on Thursday evening,” Mr Fitzpatrick said.
“Our staff were able to respond quickly and Kumbuka was tranquillised and returned to his dens.”
Mr Fitzpatrick would not confirm if there were keepers in the area at the time and said the public gorilla viewing zone had only a “handful” of people there.
He added: “At no time were any of our visitors in any danger. The gorilla did not get out of the safe space, there were only about 100 visitors.”
Neuropsychologist Jonathan Mall was at a conference at the zoo and saw at least 20 people armed with large guns arrive at the exhibits after the alarm was raised.
The 33-year-old, from Hamburg in Germany, and other visitors were forced to hide inside a bird attraction, stranded for around half an hour while staff brought Kumbuka under control.
He said: “I was kind of scared, to be honest, because we were in a really closed space where everything is green and beautiful but there could be a gorilla hiding behind every bush.”
According to the zoo’s website Kumbuka is one of at least seven gorillas living in its Gorilla Kingdom.
The £5 million section was opened by the Duke of Edinburgh in 2007, then the largest investment at the zoo for 40 years.
The same year there were warnings that animals could escape unless security was improved.
A report said that although it had no concerns about animal enclosures, in the circumstances of a dangerous animal escaping it was “unlikely” the existing perimeter fence would be sufficient to contain dangerous animals.
It warned that if they escaped there would be nothing to stop them roaming free, and said marksmen with tranquilliser darts would have little time to react.
The year before, 12 squirrel monkeys escaped from their enclosure.
In May a gorilla was shot dead by keepers after it grabbed a four-year-old boy who fell into a moat at a US zoo.
Harambe, a 17-year-old, 400lb-plus male western lowland, was killed after he dragged the youngster around for 10 minutes after he fell 12ft into the exhibit at Cincinnati Zoo.
Zoo officials made the decision because they felt the boy was in a “life-threatening situation”.