The quartet that is the United Kingdom is sounding discordant. The lack of harmony stems from Scotland's growing resistance to playing second fiddle to England. In its turn this has fuelled English resentment at the price of keeping the group intact. It is time for a dispassionate look at what solo careers might mean - a process that several other multi-nation states have had to engage in, with varying degrees of difficulty.

History and politics are raising the emotional temperature of the relationship between England and Scotland. It is a potent coincidence that next May will be marked both by the 300th anniversary of the Act of Union, which brought the two countries together, and by elections to the Scottish parliament. A recent survey suggests that just over half of Scots favour Scottish independence and that almost three-fifths of English do too.