Lol @ "England wouldn't let it happen"
The last polls showed that a higher percentage of Englanders wanted Scotland to go independent compared with the Scots. For the SNP to have the best chance of getting what they want, they would have needed the vote to be English only, haha.
Don't confuse England with Britain/UK. England is the one that's been around for over a thousand years with an incredible history, with a large part devoted to being INVADED by Scotland. The UK is the bastard child that was forcibly created by a SCOTTISH, not English, King.
As to what would happen?
No more UK. I don't see England, Wales and Northern Ireland staying together. The Labour party will be destroyed and England will be run by a less communist, more free, more eurosceptic government.
Scotland would remain a monarchy. The SNP hate it but the majority of the Scots love it as much as the rest of the UK.
I'd propose that the UK seat on the security council be given to the Commonwealth. Share it between England, Scotland, Canada, Australia etc on the condition that France gives it's seat to the EU.
Once everything's done, England should help finance the Shetlands campaign for independence from Scotland. The oil belongs to the Shetlanders. HANDS OFF SCOTLAND!