Boris,
*Italy has had low growth, but this is down to decisions made by Italian governments, as are Greece's woes.
Spain has grown in the last few years, albeit slowly, although this is very in line with its historic and pre euro growth.*
Well, that is very much your opinion, isn't it? Are you seriously saying that being locked into an overvalued currency has no effect on growth?!
*"Imagine if Italy decided to leave the Euro and defaulted on its Euro debt?"
An unlikely situation, and one which would see Italy damaged for decades, as it would not be able to borrow any further funds by issuing bonds.
What would happen to the UK if it defaulted on its debt? Fantasies are not reasons for decisions.*
Fantasies? Well, firstly, you are showing a lack of understanding about home currency debt versus foreign debt. The UK can print GBP so there is no reason for it to default on its debt. The Italians cannot print Euros or devalue the Euro so, at some point, they may decide it is just not worth taking the pain of austerity (this is an issue right now).
They would indeed be locked out of the debt markets but the financial system is remarkably forgiving (look at Argentina and the Rouble default in the 1990s). They would not necessarily be locked out for that long.
And, if an Italian default is my 'fantasy' why do BTPs trade at a significant (currently 200+ bps) spread to Bunds? As of 5th Feb, the 5 year credit default swap is trading at around 212 bps, implying a probability of default of 3.5% or about 1/28 (far too sanguine in my opinion, but let's go with the market).
Well I have a gun with 27 empty cartridges and 1 with a bullet in it which will economically blow your brains out...so, in Clint Eastwood's immortal words: ‘You've got to ask yourself one question. Do I feel lucky? Well, do ya, punk?’