Beware of bubbles. Tulips, the dotcom boom and pre-credit crunch real estate have a lot in common; they are assets that were in vogue, became overbought and eventually fell to earth. And now it’s gold.

Historically, two-thirds of gold demand comes from the jewellery industry and from countries like India and China. The remaining demand is generated by investors, manufacturing and the dental industry. But over the last four years, gold has staged a spectacular price rise and won many new investors. Everyone from hedge funds to individuals has jumped in, seeing gold as a way to improve portfolio diversification. Today portfolios often allocate 5 per cent or more to gold. A decade ago such an allocation in sound investment circles would have been heresy.

Market dynamics have changed too, with investors playing a larger part in what is driving prices higher. Now private investors hold over 30,000 tons of gold, more than the entire holdings of all the central banks on the planet. In short, gold fever has arrived on both Wall Street and Main Street. But all fevers eventually break.