Inside investment: Swan barbie

Tom Sharpe’s comic novel Porterhouse Blue begins with an account of the annual College Feast. "No one, not even the Praelector who was so old he could remember the Feast of ’09, could recall its equal – and Porterhouse is famous for its food. There was Caviar and Soupe a l’Oignon, Turbot au Champagne, Swan stuffed with Widgeon, and finally, in memory of the Founder, Beefsteak from an ox roasted whole in the great fireplace of the College Hall."

Porterhouse, a fictional Cambridge college, was given special dispensation by the monarch, back in the mists of time, to serve swan. This particular water fowl has not been popular table fare since the Middle Ages. However, it has achieved an enormous following among commentators on financial markets. The Black Swan: The Impact of the Highly Improbable has become a bestseller. Since the market dislocation that began...