JACK was wearily trudging home, lost in his own private thoughts, when he heard a voice.

"Stop!" it said. "Stand still! If you take one more step, a brick will fall down on your head and kill you!"

Jack stopped and a split second later a brick fell right in front of his feet. Rattled, he walked on.

A few minutes later, he was about to cross the road when he heard the same voice shouting: "Stop! Stand still! If you take one more step, a car will run you over and kill you!"

Jack did as he was instructed and, sure enough, seconds later a car came hurtling round the corner, just missing him.

Jack's heart was beating furiously. "Where are you? he called out. "Who are you?"

Slowly, a shimmering shape appeared and manifested itself as an old, kindly-looking gent. "I am Clarence, your guardian angel," said this vision.

Jack just managed to fight back an impulse to punch him on the nose. "Guardian angel, eh?" he yelled. "Where the hell were you on my wedding day?