Posted this yesterday and it is firming up as a valid Scottish political move as the EU was buried in the Good Friday agreements as it was buried inside the Scottish and Walsh devolution agreements....appears that all three have actually a veto voice in Parliament as the EU membership was the assumed basis for all their agreements.......

Appears Boris the "terrible", UKIP, BNP. Labour and especially Cameron simply forgot to check their own agreements.....

Scottish First Minister Nicola Sturgeon says Holyrood could effectively block UK's exit from the EU by vetoing it
http://bbc.in/29bGdrJ

Tend to believe the Scots definitely got UK constitutional advice before they went public with this.....