As someone who lives in Spain, but whose income (like I’m sure many of the other people on here) is in Sterling, I would love nothing more than to see Spain leave the Euro.

However, I cannot see what the mechanism for withdrawal could possibly be?

From another forum discussing this exact subject:

As other posters have pointed out, Spain would only leave the Euro for the purpose of cutting interest rates, devaluing the currency and trying to kick start their economy back to life.

I think the biggest practical problem they would have in trying to do this would be how to handle the currency swap, given that anyone holding Euros would have a huge incentive to hide them under the matress / take them across the border and wait until the devaluation before swapping them back into “new” pesetas. Why would anyone leave their Euros in a Spanish bank account and wait for it to become worthless?

The implications of this would be a complete collapse of the spanish banking system, massive capital flight and huge distributional inequality between those who had euro-denominated assets that avoided redenomination and those who didn’t.

Interestingly, it would be much easier for a country at the other end of the economic scale to leave the euro – ie one which has an overheating economy with a current account surplus, and needs higher interest rates and revaluation.