A group of chimpanzees fled Belfast Zoo by making an escape ladder.

Chimp

Chimp

Zooekeepers say the cunning primates used branches weakened by a storm to make a ladder and flee from their enclosure.

Alyn Cairns said trees in the chimp's area had been weakened by recent storms which allowed the clever animals to break them and then manipulate them into a tool for their great escape.

The keeper told the BBC: ''They're intelligent primates and know they're not supposed to be out of their enclosure, so got back in themselves.''

A video filmed on Saturday by visitors to the Northern Ireland zoo showed several chimps scaling a wall and sitting on top.

One chimp was even filmed walking down a path outside the enclosure.