In pictures: Shaun the Sheep

The sheep's eyes have tiny holes so they can be painstakingly manipulated to make them look left, right, up, down… or just sheepish.

Each animator also has scores of specially-made eyelids – tiny pieces of purple dome-shaped plasticine that can be added to the eyeball make the sheep blink, or look sleepy.

Because the sheep do not talk, their expressions are used to tell the story or deliver a well-timed comedy moment.

"Those eyelids are the bane of animators lives,” laughs Chris.