Harrowing film of the death of the world's most famous polar bear emerges amid fears over his treatment

This is the moment Knut, the world's most famous polar bear, died as he had lived his controversial life - in captivity and in front of a crowd of human spectators.

After compulsively turning in circles, he convulsed violently on his favourite rocky perch, let out a blood-curdling scream then fell dead into his enclosure's water pool.

The final, horrific moments of the world's most famous polar bear were captured on a tourist's video camera at Berlin Zoo on Saturday.

In the deeply harrowing film, spectators' whoops turn to screams as the realisation dawns that Knut's wild convulsions are not one of his usual playful performances.