Colchester Zoo's hugely popular lioness Naja has passed away after suffering from heart disease.

In a statement released following her death, the zoo said that 18-year-old Naja "wasn’t quite herself for a few days".

Tests revealed that she was suffering from severe heart disease and a possible thrombosis.

After initially responding well to treatment, Naja's health began to deteriorate over the next 24 hours so "the difficult decision" was made to put her to sleep last Friday.

Colchester Zoo said: "It’s always hard losing one our animals and it’s even harder when that animal has become a big personality within the Colchester Zoo family.

"Not only will all the staff at Colchester Zoo miss Naja, but she also leaves behind our male lion, Bailey."

Naja and Bailey used to share an enclosure with Naja's sister Malika, who passed away in 2020.

"All three lions had a strong bond, with the bond between Bailey and Naja made even stronger with the loss of Malika.

"Naja arrived at Colchester Zoo in 2010, along with Bailey and Malika, and since became a firm favourite amongst visitors with many photographers capturing her spirit on camera."

Emma, carnivore team leader at Colchester Zoo, said: "Naja was truly one of a kind.

"Her personality and character set her aside from any other animal we’ve had the pleasure to work with.

"Naja had a gentle side where she would interact with her keepers but very quickly changed when food was available.

"It never gets any easier losing an animal you’ve cared for and Naja will be sorely missed by the team."

Colchester Zoo added: "The Animal Care Team will be keeping a close eye on our male lion, Bailey, as he adapts to life on his own."