I have read with interest the other day when Labour lost the General Election, they did this by losing 100 seats aprox but gaining 4 times that in local Council seats. You would not think that would be the same results of two elections held on the same day.
I guess if you analysed that, places like Wigan would be a good reason why that is. Whilst over the years Labour Voters have been dismayed at the Labour Government they simply did not come out before and vote but as soon as they know the Labour Government is going to go out they come out to try and save them and vote at the General elections in places like Wigan hoping that a massive turnout would save them.
My theory is simply a view at this point but I don't think to far away from what happened. It will be interesting what happens at next year local elections to see if the above trend was a one off because of the General Election or is a new trend.