With all the crisis and panic over the current eurozone crisis, the debates primarily being about the past and not the future, not actually discussed much the consequences of what is unfolding before our eyes. All the talk now is about "fiscal union" as well as the "monetary union" that the eurozone already was: the latest I've read is that budgets would be submitted to Brussels for approval before going to national Parliaments. There seems to be a clear shift now then to the 'centre' of economic power.
Depending upon how the power gets used, he who controls the purse strings calls the shots. To have national Parliaments lose control over their own budgets, not just in a time of crisis while seeking a bailout (that already happens if the IMF get involved, but that's merely a price paid for the help) but in ordinairy times too, seems a big step towards unifying the nations into a single nation-state.
Even before this crisis, the odds were now well stacked against the UK ever joining the Euro. Largely due to fears over sovereignty and fears about a mere monetary unions becoming more ... now those fears are being realised I can not imagine the UK in the next few decades not just years joining the Euro. If the Eurozone becomes a single country that'll have interesting consequences then upon us.