By Duncan Bartlett
Europe business reporter, Brussels
The European Central Bank monitors the financial sector constantly
The deepening crisis in the US banking system is causing alarm in Europe.
There are worries that if a huge European bank, equivalent in importance to Lehman Brothers, faced failure, there would be no way to rescue it.
Up to now, it has been down to individual European governments to come up with the money to keep troubled banks afloat.
Recent examples include Northern Rock in the UK, Roskilde in Denmark and Germany's IKB.
However, those banks are relatively small compared with the huge cross-border financial institutions that have developed in the past decade.
If one of those faced bankruptcy, it would cost tens of billions of euros to rescue it, perhaps even hundreds of billions.
Governments would balk at the price and voters would ask why the French or British taxpayer, for example, should pay to support a bank that does most of its business in other countries.
One option to share the burden of the banking crisis is to ask the European Central Bank to take on the responsibility for bailouts.
That would be a major new role which goes beyond its present brief.
It would not be easy to arrange.
Firstly, the ECB would have to amass a large fund to handle such rescues.
If and when it did step in, there would almost certainly be political squabbles about which countries' banks it should help and how much money it should offer them.
However, the ECB is constantly monitoring what is happening in the financial sector in a way that individual governments cannot.
They often do not have the expertise or the information to check the financial health of big banks, especially those with complex international operations.
"It is very difficult to see through the accounts to assess the level of risk," says Nicholas Vernon an economist at Bruegel, a Brussels-based research group.
"There have already been many surprises and now due to the environment with Lehman Brothers, we are likely to have other surprises down the road."
The answer, he thinks, is to develop better communication links between all the teams that supervise the banking industry across Europe.
This was a plan supported by Europe's finance ministers when they met in Nice at the weekend.
However, with the banking crisis gathering momentum in the US, it may not be long before Europe is forced to make some tough and expensive decisions about how to ensure its banks avoid a similar fate.