George Osborne, Chancellor (Treasury Secretary) of the UK:

"If you're in a single currency as the UK knows, as the US knows, you have to transfer fiscal resources around the countries to make good the differences in regional competitiveness," he said at the World Economic Forum in Davos.
"To make the single currency work in the long term, there are going to be permanent fiscal transfers in my view. That can be done in an opaque way, through a central bank, it can be done in a semi-opaque way through eurobonds, or it can be done through direct budget transfers, but that is what's required to make a single currency work."