Visitors were evacuated from Chester Zoo on Sunday – and hundreds more turned away – when 30 chimpanzees escaped from their enclosure
The primates broke out of their secure confines into a keepers’ area where their food is prepared.
Staff, experiencing one of the busiest days of the year, were forced to shut the 110-acre site as a precaution.
They then attempted to round up the animals, described as very strong and intelligent.
A zoo spokeswoman insisted members of the public were never at risk.
An Irish family visiting Chester was among the visitors in the zoo when the animals escaped at 12.40pm.
They said: “Everybody was told to go because chimpanzees had escaped. We didn't really know what was going on but it was quite scary.
“We were just having lunch and we were told to go into the restaurants and shops, where we stayed for about 45 minutes.
“Luckily we were in there for three hours so we had a good day.”
Other visitors were locked in the jaguar enclosure while staff ensured there were no chimps in the public area.
One said: “It was quite calm, people were joking about. No-one was really panicking.”
Many zoo visitors queued for refunds following the evacuation.
Staff handed out bottles of water to those stuck in traffic and waiting for buses.
Zoo staff faced a tough challenge to regroup the chimpanzees, considered the most intelligent non-human primate, but managed to have them all back in the enclosure within four hours.
No visitors or staff were injured.
Chester Zoo PR and media manager Rachael Ashton said: “We don’t know how they managed to get there and in the time I have been here I have never known it to happen.
“None have got into the public domain but because they are primates we closed the park as a precaution.
"We apologise for any inconvenience this has caused to our visitors and would thank them for their full co-operation and patience."
Around 1.4 million guests will visit the zoo during the course of the year, making it one of the UK’s most popular tourist attractions.