George Osborne made his first public intervention in the debate on Scottish independence when he told the Scottish people that they might end up adopting the euro.But would Scotland be a new member state? There is no real precedent for this situation. Arguably, the dissolution of the UK would divide a member state into two new entities but, as both these entities had formed part of an existing member state, there should be no provision necessary for new membership as such. (I accept that there would need to be treaty adjustments but that would not necessarily ential the admission process.)
The SNP has said in the past that it would see euro membership as a long-term aspiration for an independent Scotland, though this would have to be approved in a referendum. All new member states are obliged to give an undertaking that they will join the euro when they meet the Maastricht criteria.
Furthermore, what would be the position of the England plus rump? If Scotland had to apply formally for EU membership status, would not England have to do likewise? Thus the potential requirement to join the euro might apply to both Scotland and England.
Finally, this is not going to happen in the near future. The referendum is likely to take place in 2014 and, if independence was chosen, there would be a lot of subsequent negotiation to hammer out the details. Who knows what the relative positions of the euro and the pound sterling would be after 2015?