Tender women: Decorative images of women have been a recurring theme on banknotes since the 17th century. Iain Gale put his hand in his pocket

The Queen looks up from a five-pound note with a serene smile, her presence transforming what was a mere piece of paper into something of real value. But what of the other side? For hundreds of years, bankers have debated long and hard over what or who to show on the reverse of their currency. And nine times out of 10, the answer has been a woman.

An exhibition at London's British Museum demonstrates how frequently, since the Bank of England chose to decorate its first notes (issued in 1694, with the figure of Britannia), women have featured on banknotes. They were no fools back in the Glorious Revolution. Britannia's presence was intended as much for decoration as to subvert our natural perception of the nature of money itself.

When you characterise a note with the image of a national hero - the Duke of Wellington, for example, was until recently on our own fiver - you lend it something of the perceived characteristics of that person. Thus, the old five- pound note came to have a feeling of the tenacity, integrity and fortitude which history attaches to the victor of Waterloo.

Imagine the effect of marrying a national icon to a pretty face. Your note becomes immediately more attractive; a thing not only to be admired but coveted. Britannia, with her pleasantly Amazonian features and her allegorical significance of nationhood and endeavour, provides an ideal combination of the two. Similarly, while the French 100-franc note might carry the head of the painter Delacroix, he is only there as an adjunct: it is his half-naked creation, La Liberte, who dominates the note, bringing to it all her symbolic attributes. If, in Britain, money is a national birthright, in France the implication is that it will set you free.

One thing which unites most of the figures of women on banknotes, however, seems to be their ample proportions. The Swedish Svea, for instance, on their 10-krona note, would be more at home in a Russ Meyer movie than sitting decorously with her pet lion in the national vault. If not shown bare- breasted, as in France, many of these women seem to have been dressed by Jean-Paul Gaultier. As a slight variation, the 1950s Swiss 50-franc note shows a mother breast-feeding. Either all bankers are mammary fetishists or there is some more profound reason at work. This, of course, is fecundity.

Even in the post-feminist world, women are still acknowledged as the bringers of life. A banknote bearing a fleshly mother-figure subtly implies growth. Often fruit itself is also present, reinforcing the prospect of a fertile economy. Money may make the world go round, but not without some help from mothers.

If this fascinating show has a subtext, it must be the irony that while women continue to feature on currency, the world's financial institutions are still male-dominated. And while this hegemony remains in place, the nature of women's popularity with those who approve the designs for banknotes will not change. Recession may deepen, the pound may be devalued, but with a pretty girl or a caring mother-figure in your pocket, you somehow just know that things can only get better.

'Beauty and the Banknote', British Museum, Gt Russell St, WC1 To 18 Sept

(Photograph omitted)