All kinds of monkey business has been going on at Chessington World of Adventures, which formally welcomed the newest addition to its animal family.

Gorilla Shani, 15, amazed staff and guests by giving birth to baby boy Kumi right in front of their eyes very rare behaviour for a gorilla.

She delivered her third baby four months earlier than expected.

Kumi, meaning 10th, was the second gorilla born into the 10-strong family this year and his arrival confirmed the Leatherhead Road park's status as one of the top breeding centres in Europe.

Keeper Michael Riozzi said: "Shani was still rearing her second child Shanga when she conceived, which is most unusual. It is a fantastic surprise to have a second gorilla birth so soon after the arrival of Kumili in January."

The birth of the 3lb baby four months ago was the seventh at the park. Pregnancy in gorillas lasts up to nine months.

Both mother and son are doing exceptionally well.