It will be interesting to see how the banks that encouraged Eastern Europeans (not just in Hungary) to take Swiss franc loans react to potential defaults. While not of the same size as the US-based mortgage defaults of 2008, the danger of an untidy break-up of the Euro may become signposted by this action.

Of particular note will be the reaction to a Syriza victory in Greece; will Germany consider the danger of major defaults by Euro mortgage holders (as well as the government debt) when deciding how 'generous' the EU should be regarding keeping Greece in the Euro?

It is urgent that the current "there is no Plan B" attitude be changed to one of preparing for the worst, i.e. the exit by the most debt-ridden countries from the Euro, creating another banking crisis.

The consideration of revaluing the strong currencies of Germany, in particular, has far less risk, allowing the Euro to drop to a realistic rate for the poorer countries.

Whatever else can be done, the reduction of cash holdings is an important step, by the withdrawal of all notes above, say, 10 Euros, to avoid rewarding the speculators - and, at the same time, greatly reducing the hundreds of billions lost to tax evasion.

What Switzerland has done is given us a sharp reminder that printing more and more money is not the long-term answer; what is not clear from their extraordinary action during trading hours, is whether it is too late already?

But whatever else happens this coming week, let us hope that Plan B is not just a dream but being prepared as a matter of urgency.