To what extent is Britain (or the British Isles) the same kind of construct as Scandinavia (or the Nordic countries)?
Both Britain and Scandinavia have a long and complex history, with periods of political unification and others with separate kingdoms and plenty of wars.
Scandinavia's united period was a long time ago (1397–1523), while Britain only started falling apart when Ireland became independent again less than a century ago. On the other hand, the British Isles are to some extent more heterogenous than Scandinavia – the former is a mixture of Celts, Anglo-Saxons and Norman French, while the latter consists of the descendants of the Vikings with some Finns, Lapps and Germans thrown in.
In both cases in can be hard to pinpoint exactly what Britishness/Scandinavianness means. For instance, John Major's description of Britishness – “Britain will still be the country of long shadows on cricket grounds, warm beer, invincible green suburbs, dog lovers and pools fillers and, as George Orwell said, 'Old maids bicycling to holy communion through the morning mist'” – is so clearly a description of England that does not apply to Scotland and Ireland. In the same way, it's very hard to define Scandinavian culture in one sentence. And yet, Scandinavians do recognise the similarities intuitively, and Scandinavians abroad tend to hang out together, for instance at international conferences.
So there are definite similarities. And just as Scandinavia does exist in spite of having been separate countries for half a millennium, Britain will always exist whether Scotland becomes independent in 2014 or not. Actually, Scottish independence might actually lead to a reevaluation of the concept, so that it ceases to be about a political construct and starts being about what actually binds people on these islands together, whether they live in Ireland, Wales, Man, Scotland or England.