HSBC has tested its cash machines in Greece to check whether they could cope with the reintroduction of the drachma if the country drops out of the euro.
It is the clearest sign yet that the international financial sector believes Greece is on the brink of quitting the single currency and returning to its former currency.
An HSBC spokesman said: 'Like all banks, we have been working with regulators to undertake preparatory work at multiple levels in the event of a sovereign default, an exit from the euro, or any other eventuality.’
Greece faces an election on June 17 that is widely regarded as a vote on whether to stick with the euro.
Banking sources noted that it was the fear that Royal Bank of Scotland customers would not be able to withdraw their money from ATMs that marked the high point of the financial crisis in Britain in 2008 when the Government intervened to prop up RBS and the rest of the banking sector.
The cash machine tests at branches in Athens are understood to have been extensive to ensure that the machines are able to handle banknotes of a different size and texture.