Knut now weighs 22 stone and has six-inch claws and a fearsome set of fangs to match.

And he seemed to be particularly keen to test them on the three-year-old boy lying on the ground next to his enclosure.

Knut was rejected by his mother at birth in December 2006.

But his days of being picked up and cuddled are long gone.

He is, after all, a wild animal and now not even the keeper who raised him by hand dares to get close.