Chester Zoo has condemned a group of "irresponsible" trespassers who filmed themselves breaking in to an enclosure at the popular tourist attraction.

The zoo is taking legal action after footage of the incident was posted on YouTube. 

They allege that zoo property was damaged during the break-in, which they say also startled a Grevy’s zebra causing it to suffer an injury to its hind leg.

Jamie Christon, Chester Zoo's chief operating officer, said: “We’re aware of the small group who trespassed onto the zoo site a couple of weeks ago and we are taking legal action.

“There was damage to zoo property including a set of customer toilets following the trespass. It appears that the group also startled a Grevy’s zebra, an endangered species who we care for as part of a Europe wide breeding programme, as the animal had an injury to its hind leg following the trespass. Thankfully the animal has since been making a good recovery, helped by our senior keepers and veterinary teams who were quickly on site.

“With over 15,000 animals in our care, including large carnivores and predators, trespass onto the site is both unacceptable and extremely dangerous. The members of the group appear to have little or no regard for their own safety, or the safety and welfare of the animals.

“We condemn the irresponsible actions of the group and are taking the matter extremely seriously.”

The YouTube video shows a group of vloggers – video bloggers – taking part in what is billed as an ‘overnight challenge’, part of a series of daring stunts. 

Shot at night time, the video shows glimpses of various animal enclosures and at one point the group appear to be inside one of the enclosures – but they run away fearing they have disturbed an animal. 

The footage has since been removed from YouTube.