Two fell runners are running across a remote moor when one suddenly cries out and falls to the ground.

He doesn't appear to be breathing and his eyes are rolled back in his head, so his friend panics and calls 999 on his mobile telephone.

''My friend is dead!'' he cries. ''What can I do?''

The operator, speaking in a soothing voice, tries to calm him down. ''Just take it easy. I can help. First, let's make sure he's dead.''

The line goes silent for a moment and there's a loud bang before the man comes back on the line. ''Okay,'' he says breathlessly, ''Now what?''