It has been brewing for a while. English people are becoming discontent with several things
1. Labour is only able to win a majority at Westminster due to the large number of seats they win in Scotland. Without them, the conservatives would be permanently in government in England.
2. The number of Scottish MPs is disproportionately large with respect to the size of their population.
3. Many of the senior figures in the Labour party are from Scotland, the so-called "Scottish Mafia", and resentment is beginning to rise in England that our affairs are being run by MPs, who, if there was a fair constitutional settlement, wouldn't even have a seat in an English parliament.
4. Scotland is heavily subsidised by English taxpayers. It has pretty much become a socialist satrapy.
Labour's recent attacks on the SNP have got nothing to do with preserving the Union, about which they care little, but everything to do with ensuring Gordown Brown (another Scot) can become the next Prime Minister of the UK, rather than simply the Prime Minister of Scotland.
Alas for Labour, I think the cat is out of the bag now. The current situation is unsustainable. However, I don't expect a large change immediately, I suspect it will take about 10 years.
I think you will find out that it is Scotlands oil that has subsidised England since the 1970's.
Why are there more Scot MP per capita than elsewhere in the UK ? I don't get this...