Simon Calder visits the British Museum's new Money Gallery
Swindon: that would be the ideal location for a brand-new Money Gallery. The Mondex project in the Wiltshire town, aimed at creating a cashless community, means that hard currency is closer to becoming a museum piece in Swindon than anywhere else in Britain.

But, on the basis that London has a bigger catchment area, the Hong Kong and Shanghai Bank - which owns the Midland - has stumped up for a rich new exhibition hall in the British Museum. The Money Gallery opened yesterday. And like any decent savings account, it is already attracting interest.

From the main entrance to the British Museum, battle your way through the swirling coachloads and ascend the main staircase - which looks as though it could be modelled on the approach to a moneylender's temple. Swing round to the right, and locate room 68, an icily pale-green chamber full of exhibits worth their weight in gold (or silver, or bronze).

The basic principles are as sound as the Bank of England. Four millennia of money, from Mesopotamia to Mondex, are traced out in a room the size and shape of a long, thin, high street bank.

Ancient accountants set the tone, with the ancient equivalent of a till receipt: a clay tablet issued in Ur, now in Iraq, in 2046BC. It records a transaction where seven oxen could be bought for seven-and-a-half shekels each.

The remarkable thing about the ancient coins is how little they have changed. The first recognisable tokens, made of gold and silver as a measurable and portable store of value, were issued 2,500 years ago in what is now Turkey. Shortly afterwards the first forgers started work, plating base metals to look like solid gold coins. Government financial crises were not far behind: at the time of the Peloponnesian War in 407BC, the Athenians were so strapped for cash that they melted down the statues of Victory on the Acropolis to make coins to finance the war effort. Two thousand years and miles away, these remain as small and bright as buttons.

Around the birth of Christ, the first experiments with the modern concept of money began. The emperor Wang Mang of China issued tokens that he promised were worth much more than the value of the metal they contained -honest. Few believed him.

It took the development of world trade to create a system of money that is not based on precious commodities. Receipts issued by gold merchants comprised the first paper money. You could use these vouchers as if they were gold coin, because they were backed by precious metals in the vaults. But the crucial message for children is what happened next. When the "Gold Standard" was abandoned (which in Britain took place in 1931), the result was a value system based upon belief; a pounds 10 note can only be worth 70 minutes of labour for the average British worker, or nearly two million Turkish lire, if society believes it to be so. This is a - perhaps the - prime example of how a community functions.

Once children have come to terms with this concept, there is not too much more to hold their interest. A giant pounds 1 coin inspires some wishful thinking among those who consider their pocket money too modest, while a big bronze cash register rings out the days when pounds 1.5s 6d would buy a good family day out rather than merely a cup of tea in the museum cafe.

A British lottery ticket from 1786 shows how ideas are as circular as coins, though the prize was rather less than tonight's roll-over jackpot. And, at the centre of the gallery, the proceeds of an unresolved court case from three centuries ago are left splaying from leather money bags: the protagonists died before the case was resolved, so the state kept the cash. And, straight from the shops of Swindon, is a Mondex card heralding the cashless society.

The $64,000 question is, how rewarding will children find the new gallery? The explanatory texts seemed aimed at 6ft bankers - who, unlike children, will find the information at eye level. Most of the exhibits are at lower altitude, but the overall impression is that the gallery is firmly for grown-up devotees of dosh. The Bank of England Museum, across in the City, is much more hands-on - but, annoyingly, does not open at weekends.

Back at the Money Gallery, though, two nine-year-olds from St Peter's School in Hammersmith were coming to terms with the implications of cash - and showing that they were already fairly financially astute:

Richard Edmond: "I liked the really big pounds 1 best - I'm bored of seeing the small pounds 1 coins, though I do like the new ones with different designs. When I saw all the money spread out from the money bags in the middle of the room, I thought `That's a lot', but then I saw that it was only pounds 75."

Lucas Summers: "I think if we still had the old money I'd feel richer. I liked the big old cash register, but I couldn't really understand the numbers on it. I try to save up my pocket money and keep it in the bank."

The deal

The Money Gallery is in the British Museum, Great Russell Street, London WC1 (0171-636 1555). The nearest tube stations are Holborn (Central and Piccadilly lines) and Tottenham Court Road (Central and Northern). Limited (and expensive) parking is available nearby.

Disabled access: lifts to the upper floor. A leaflet about facilities for the disabled is available upon request.

Admission: free, though donations are requested upon entrance to the museum, and for the introductory guide to the exhibition.

Opening times: 10am-5pm from Monday to Saturday, 2.30pm-6pm on Sundays. The museum will close on Good Friday (28 March) and May Bank Holiday Monday (5 May).

Food: there is a cafe in the museum, but it is inconveniently hard to reach from the Money Gallery. The journey involves a long walk through half-a-dozen ancient civilisations, and if you take a wrong turn you could find yourself in Assyria rather than a tea bar. Once there, the sandwich plate - a sandwich, scone and cake, plus tea - will revive children and their parents for a modest pounds 3.95.