The ape escape: How 'psycho' gorilla Kumbuka made a bid for freedom by smashing the window of a 'cracked' London Zoo enclosure - after crowds were warned about taunting him

After attempting to make a dramatic bid for freedom, Kumbuka the gorilla looked perfectly relaxed - despite being branded a 'psycho' by one of his keepers.

Zookeepers were today seen boarding up the glass partition which cracked as the 'agitated' gorilla escaped from its den - through a door which may have been left open.

Male silverback Kumbuka, an 18-year-old, 29-stone western lowland gorilla, escaped the enclosure on Thursday evening for 90 minutes.

Sitting in his hammock nonchalantly munching leaves, the silverback’s subdued mood was in stark contrast to the highly ‘agitated’ state he was said to have been in before he broke out of his enclosure.

Visitors were said to have been taunting the gorilla, prompting social media users to voice their sympathy for the animal, writing: 'We all would get nuts if we were locked in a cage and people would stare at us every day. Poor creature.' 

Staff said Kumbuka was given a chocolate chip cookie yesterday evening as a 'special treat' from his specially managed diet tailored to his nutritional needs.

Bosses denied he was to blame for the damage despite visible cracks in the reinforced glass at the £5.3million Gorilla Kingdom enclosure. 

Instead, a spokesman insisted the window had been damaged from the outside – rather than from the gorilla paddock on the inside – by a contractor carrying out repairs around a week ago. ‘Kumbuka did not smash a window in the enclosure,’ he said.

‘This morning we have been doing some work to cover that damage and reassure any concerned members of the public. We had already ordered the new panel.’ Early visitors yesterday were left waiting as the five-bar gate at the entrance remained padlocked until around 11am as keepers monitored the gorillas to see how ‘happy and settled’ they were.

The zoo refused to comment on whether a door had been left open while a ‘full investigation’ is being carried out. The 18-year-old animal got out of the gorillas’ night quarters, which is not open to the public, into another part of that section which is for keepers only.

The zoo confirmed Kumbuka got into the ‘non-public keeper area’ at 5.13pm and was back in his den at 6.21pm after being tranquillised.

The incident comes amid warnings from one zookeeper, who allegedly told BuzzFeed news: 'He's a f*****g psycho, that ape. He's smacked the enclosure glass a couple of times.' 

It was initially reported the animal may have smashed the glass partition surrounding its indoor den - but now it has emerged a door may have been left open. 

A source told the Evening Standard: 'Every enclosure has a gated area which is off-limits to the public to stop animals running straight past when the door is opened. That door shouldn't have been left open.'