A zoo spokesperson said: “It has been part of the zoo for nearly three decades but since its installation in 1991 the zoo has grown in size and the transportation system now doesn’t even cover half of the 125 acres. Over the last few years we have experienced both system and train failures so this once state-of-the-art system is proving costly to maintain and unreliable for visitors.”

The monorail will be operating for the next couple of months but is due to close in late summer.