FIRE crews were early today trying to dig out a youth trapped under 12ft of earth. He is only alive because a clay boulder which is pinning him down kept the full force of a landslide off his body.

The teenager, who has not been named by West Yorkshire Fire Service, became trapped last night when laying pipes in a 20ft deep trench in Yeadon, Leeds. The walls of soil collapsed on top of him.

A fire service spokesman said: ''They are taking it very carefully because they do not want the whole lot to come down on top of him. We are hopeful we are going to get him out, but it is likely to take quite a while.''

A miniature camera similar to ones used in finding earthquake survivors located the youth and has shown he is still alive. An airway has also been put down to him.

The spokesman said: ''He is complaining of suffering a lot of pain, particularly in his legs, but anything could have happened to him. We take it as a good sign he is complaining because he is able to talk.

''A large clay boulder about 6ft by 4ft pinned him down and in effect saved him by keeping a lot of the soil off him.''