The European Central Bank (ECB) has confirmed that the 11 economies participating in the euro have managed "a successful conversion" to the single currency.

The BBC's Peter Morgan: "Glitches are inevitable"

The merging of ten European currencies into one has been probably the biggest number crunching exercise in economic history. The work began immediately after Thursday's announcement of the conversion rates for the national currencies into the euro.

Germany's Dresdner Bank says "everything has gone well"

The world's bankers had only three days to convert all accounts into euros and check that their computer systems can handle the new currency. When trading starts on Monday morning in Asia's big financial markets, they have to be ready. Sydney, Australia, will be the first major market to trade the new currency and it will open at 0500 local time, which is early Sunday evening in Europe,1800 GMT.

If Europe's central bankers, share brokers, investment fund managers, commercial bankers, currency dealers and bond traders bungle the job, the new year will begin with economic mayhem. Millions of dollars (or rather euros) could be lost.

Experts predict that there will be some mishaps and failed trades, but across Europe more and more banks and other financial institutions are giving the 'all clear'.

The conversion to euros is actually ahead of schedule. When banks rehearsed the changeover they had only slow back-up systems available; for the real thing they are using their fast main computers.

Banks have to be ready when the first euro cheques will be written on Monday, 4 January

The exceptionally low trading volumes on the financial markets before and after Christmas is speeding up things too as fewer trades have to be converted into euros.

Manfred Körber, spokesman for the ECB, said that "everything is running according to plan" and banks and stock markets across the continent are confirming this view.

The Bourse de Paris and all financial firms dealing at France's main stock market announced as early as Saturday evening that they had completed their euro preparations "without a hitch".

Germany's Deutsche Börse and the Association of German Banks reported a smooth transition as well, while the Bank of Italy denied rumours that there had been trouble at the Milan stock exchange. A bank official said: "We have not sign of any problems; the bourse is ready for January 4."

Problem-free London

Europe's biggest financial centre, London, has stayed out of trouble too. The British Bankers' Association is operating a helpline this weekend, but an official said that "we haven't really had any call on it, so presumably no one has any problems."

In the City, bond traders at Barclays Bank convert their eurozone accounts

The Bank of England reports that it was more confident about the likelihood of a smooth euro market debut after talking to all major London market participants and bankers are satisfied that their years of preparation have paid off.

Anthony Davies, euro-conversion managter with Chase Manhattan in London, said: "I'm pleased to say things are going really well."

Most banks and markets will now spend the rest of Sunday to test their systems and make final adjustments.

The real thing

Nonetheless, nobody wants to predict that Monday's trading will be trouble-free. Belgium's euro coordinator, Guy Quaden, said: "Everything has been prepared and simulated. But on Monday we have to deal with reality."

David Clementi, deputy governor of the Bank of England: "The markets are well-prepared"

And David Clementi, deputy governor of the Bank of England, warns that it "would be surprising if it (the changeover) was entirely trouble-free". He says that the Bank of England will carefully monitor the situation: "It is possible that we shall have problems on Monday, that later in the week we will find some failed trades, some payments that were sent to the wrong banks ... everybody is alert for that."

The tricky bit is that during the transition period financial institutions depend on each other. If a bank, a fund manager or a trader gets it wrong, their business partners and especially their customers and investors will suffer. This can cost a bank a lot of money and if the mistakes are big, the whole system could suffer as confidence in the euro might falter.

Zbynek Sokolovsky at Dresdner Bank in Frankfurt says: "The champagne corks will pop on 5 January - if everything has gone well." But Philippe Batchevitch of Credit Agricole Indosuez, a large French merchant bank, is unfazed: "It will all get off to a gentle start."

The task

Getting Europe's financial markets euro-ready has been an enormous task.

• Every share price of every single company listed in the eurozone was recalculated in euros.
• The foreign exchange markets had to redenominate billions of euros worth of currency transactions.
• The total government debt of the whole 11-country euroland, i.e. government bonds and treasury papers, and all corporate bonds were transferred to euros.
• Millions of accounts in francs, guilders, Deutschmarks, schillings and other currencies had to be converted.
• And finally, many banks in the eurozone moved their own business into euros and therefore had to recalculate their books and all historical data in their ledgers.

Big banks spent years preparing for the changeover. Computer systems were updated, software rewritten, new financial and accounting software introduced that can cope with the new currency.

During the transition weekend some banks worked 24 hour shifts and booked hotel rooms to keep vital staff nearby. New Year celebrations were reduced to a sip of champagne, as technicians and bankers went through piles of flowcharts and computer printouts.