From 1 January 2002, 12 currencies will be consigned to souvenir status. The Independent's travel editor turns out his pockets for a European spending spree

Constancy. That is what 1 January 2002 will mean for the people of a dozen European countries. In the wake of the mightiest monetary transformation in history, the cash they spend will stay constant from Athens to Athlone. It is also where I happen to be, nearly. Specifically, I am at the bottom of Germany, at the end of a pier that juts out into the country's largest lake. Both the handsome city and the murky lake are called Constance.

Constancy. That is what 1 January 2002 will mean for the people of a dozen European countries. In the wake of the mightiest monetary transformation in history, the cash they spend will stay constant from Athens to Athlone. It is also where I happen to be, nearly. Specifically, I am at the bottom of Germany, at the end of a pier that juts out into the country's largest lake. Both the handsome city and the murky lake are called Constance.

The water is the same heavy shade of grey as the five-euro note: the lowest common denomination, and therefore the bill destined to become the scruffy runt of the single European currency. For British travellers, it will soon become as familiar as the dollar bill – and several times more valuable. Getting through the metal detector at Luton airport this morning was tough. The security staff looked surprised as I emptied my pockets and produced jingle after jangle of what are now known as "legacy currencies". The cash confusion that surrounds the business of pleasure in Europe, and occasionally traps unwary travellers, has only one more month to go. Starting on New Year's Day, 12 national currencies – including two kinds of mark and three varieties of franc – will be consigned to the small change of history.

The easy way to remember the participating nations is the acronym BAFFLING PIGS: Belgium, Austria, France, Finland, Luxembourg, Italy, Netherlands, Germany, Portugal, Ireland, Greece and Spain. Each has set its own handover period, during which shoppers can spend national currencies, but receive change in euros. The Germans say the deutschmark will cease to be legal tender at midnight on 31 December. This is just a tad unrealistic, so shops are planning to accept the old currency until the end of February. Disarray is evident in the other dates: Dutch guilders bow out four weeks into the New Year, Irish punts six, French francs seven. Most of the rest will survive until the end of February. After that, you will have to change "legacy" currencies at banks or bureaux de change, and by the end of next year usually only the central bank of each nation will oblige.

Trudging down to the Bundesbank in Frankfurt in the middle of a holiday with a pocketful of loose change does not sound much fun. So, if you are a traveller who keeps foreign money from one year to the next, there is a decision to be made. Do nothing with it, or save it as a memento for the grandchildren, and you effectively donate it to the issuing nation – fine, if you feel that Chancellor Schroeder or President Chirac deserves your charity.

Talking of charity, surely the noble act is to donate loose lire and spare schillings to one of the many good causes that promise to transform old money into new benefits for the needy? Commendable, and there are many opportunities for giving. But I wanted to make a final rattle through Europe with those soon-to-be-lost coins that add an exotic dimension to a journey. Since I first travelled abroad, aged 14, and inspected with awe a Fr10 note and the lightweight coins that accompanied it, an exotic collection of cash has accumulated in my sock drawer. I was determined to savour every last sip of coffee my legacy cash could buy. So I made a sterling donation to Unicef – the charity for which British Airways collects with its Change for Good campaign – and set off to spend, dépensez, geber aus my way through a slice of Euroland, on a trip embracing scenery, history and shopping.

Travelling with me, at least in spirit, is Simon Phillips. He runs European retail operations for Travelex, the world's largest chain of bureaux de change. For the past month, we have talked about the dramatic effects the euro will have on British travellers. For a start, the potential for fraudsters to offload forged notes is enormous, given that neither shoppers nor shop staff will have handled the real thing. "Our colleagues in continental Europe will be having a terrible time for the first two months," says the Travelex man. "We're expecting a massive influx of false notes and coins." You could have problems, too, if you take cash in €200 and €500 denominations. Many retailers will decline them, rather than risk giving change to a customer buying a newspaper with a fake note worth £300.

Each of the handsome structures in the old town of Constance is daubed a different pastel shade, in the manner of the new euro notes. The effect is of walking through giant slabs of marzipan. The first DM20 of my stash is devoured by lunch at a harbourside restaurant, looking out at Lake Constance – really a large bulge in the Rhine, which then funnels into Europe's diminutive Niagara 20 miles downstream. Constance, the city, is the starting point for the Schwarzwaldbahn, a railway line that steers as straight a course as it can through the mountains of the Black Forest. Another DM40 buys unlimited travel for the day on this line, and other railways within the state of Baden-Wurttemburg.

The train cuts through a landscape strewn with elegant, skeletal trees with the skimpiest covering of leaves – an image that matches the colour and complexity of the €50 note. Soon the line describes a wide arc around a river that turns out to be the infant Danube; two of Europe's mightiest rivers, flowing to the North Sea and the Black Sea, are separated by only a narrow range of hills. Villages huddle together on the brink of winter in a landscape daubed with pale gold and subdued auburn. Today is the perfect day for appreciating the subdued palette through picture windows.

As we scale gradients and negotiate curves that cast doubt on the sanity of the railway engineer, stray pillows of cloud are strewn around like scatter cushions on the turbulent landscape. Every successive tunnel spits us out into a more dramatic scene of firs clinging to tottering mountainsides, above streams and lakes that shimmer like a sixpence (Britain's very own legacy currency). The effect begins to dissipate on the descent to the Rhine, the river that has taken the long way round.

Kehl is a tail-end of Germany, a town that, if it went any further west, would tumble into the Rhine. Evidently, it was subject to compulsory Allied redevelopment circa 1945, save for a magnificent church that commands a dowdy main square. And, if you are French, it is something of a shoppers' paradise. "It will be very difficult in January," said the man at Aktiv Musik, who sold me a David Gray CD that had unaccountably gone missing from my record collection. "Everyone from France comes to buy here, because it's cheaper. So we'll be taking francs and marks and giving change in euros."Only for a short while, mind. Once the single currency is established, cross-border shopping will become no trickier than popping around the corner for a litre of milk, at least if you happen to live next to an international frontier. Across the French border in Strasbourg, White Ladder cost 15 per cent more in the Virgin Megastore than back in Germany.

CDs apart, Strasbourg is an ideal place to offload French francs. The bridges that connect the core of the city on the Grande Ile with the mainland, and even the arches of the railway station, are mimicked by the designs that decorate the new notes. At Boulangerie Fritsch, the baker speaks French to one customer and German to the next. And, at the bizarre but splendid Winstub Zum Wynhaenel – an Alsatian restaurant that has elbowed its way into an otherwise unremarkable apartment block – you can dine splendidly on jambon et choucroute with the best Pinot Noir that Fr175.50 can buy.

The best train to Saarbrucken that Fr67 can buy will leave approximately next Tuesday, I learn when I turn up for the trip back into Germany. Une grève has shut down all but a fraction of the French rail network – "But if you run you can take the train to Nancy, and another one to Metz..."

I run, ticketless, catch the train, and see the contents of the tobacco tin marked "France" almost disappear. Not only is the journey far more circuitous than I had intended, but an indemnité forfaitaire of Fr100 is payable for buying a ticket on the train. That will help SNCF meet the wage demands, then.

Talking of strikes: the potential fordisruption of Operation Euro is vast. Financial institutions are being "front loaded" with €2,000 for every child, woman and man in Europe ­ about €600bn. Last summer, the people who put the cash in cash machines in France went on strike. At least three out of every five hole-in-the-walls became franc-free zones, precipitating numerous cases of "hole-in-the- wall-rage" as people found themselves penniless in Paris. The French newspapers warned this week of a possible banking shutdown at the start of next year that could render the country euro-free. A big risk? Simon Phillips thinks not. "We're getting more comfortable that there won't be a major catastrophe on 1 January."

Half-timbered villages pepper the line to Nancy, a phenomenon that is easy to spot because the "express" to Paris plods through them at a cautious walking pace. The serene countryside is worth half a day's time and wages, mind. The route used by the Orient Express carves through countryside speckled with farmhouses and chapels, but mostly gentle, empty hills, followed by the Marne au Rhin canal.

Halfway through an unexpected day on the rails, the city of Metz provides the ultimate euro experience. Besides the mandatory Irish Pub (called, imaginatively, "Irish Pub"), the city has a Comptoir Irlandais that sells English beer and Scottish shortbread, and an ambivalent nationality. You can carbon-date the periods of German occupation according to the weight (heavy) and colour (dark) of the imperial architecture, which contrasts with the delicate honey stone of the French buildings. At McDonald's, euro prices take precedence, with franc equivalents in more awkward quantities. Along the road at the Banque Nationale de Paris, a brand-new "hole-in-the-wall" stands on the trottoir waiting to be inserted into the wall.

Best of all, close to the strictly Teutonic railway station stands the Moselle headquarters of Unicef, with a gift shop selling a crisply designed 2002 calendar that will make an ideal stocking-stretcher at Christmas. As I am the only customer, the staff don't mind me painstakingly counting out 65 francs, then tipping the rest of the contents of the tobacco tin on to the counter with the best "Gardez la monnaie" I could manage. I have already bought my ticket out of France.

"Goethe" is a funny name for a European international train that avoids Germany. But the train bearing the writer's name, which started in Paris, fairly hurtles through the ashes of autumn to Luxembourg.

For a half-litre-sized country, Luxembourg hosts 220 foreign banks and some ambitious currency pretensions. You will find a "commercial" and "financial" Luxembourg franc listed on the international exchanges, as well as the regular "flux", as it is abbreviated. In reality, that is just the Belgian franc dressed up, so Luxembourg is a handy place to unload two currencies for the price of one. It is also the cheapest place I can find for that other worldwide currency, the Big Mac: €2.90, compared with €3.20 in France and €3.80 in Germany. I do not eat there, though; the Polish-run Brasserie Chimay delivers a delicious soup and steak-frites for three times as much.

As my pockets grow lighter and night descends, my final destination is the country's airport ­ a place, says Simon Phillips, that defines the euro experience for him. Along the way I have fretted about his future as head of retail operations in a continent where people no longer need to change money.

"We always said 31 December 2001 would be the last day for trading at Luxembourg airport. We couldn't believe there'd be any business. Until June this year, that was still in my head. But now, I think that if no one else is doing it, we should be doing it. If we can get a larger piece of that smaller business, we're very happy."

The small, two-person bureau at the airport has no customers. It would not have had me, either, except that the French rail strike kept me out of Germany; what had begun as a diversion turned into a grand tour, and I still have the German currency I had intended to spend. "How much sterling will you give me for DM40?" The answer I was hoping for was around £12. But because Travelex needs to pay its local staff and Mr Phillips, the conversion into Luxembourg francs reduced the sum to below £9, so low a level that the computer steadfastly refused to take the next stage, and make an offer in sterling. That is why a lot of people in travel believe Britain needs the euro, too. Not Simon Phillips, though. He believes: "It is going to come unless we're incredibly lucky." In this case the "we" refers to Travelex, and some Tory MPs, rather than the British public. Meanwhile, a small queue is forming behind me at the Luxembourg airport bureau de change. As long as there is a world outside Euroland, and Britain remains aloof, Simon Phillips is constantly happy.

The best website for details of the euro is