I met up with some friends who work in the National Trust yesterday and they said the main cause of most of the flooding (apart from the rain, obviously) was the increase in development up and down the river meaning more concrete and tarmac and less ground for the water to soak into.
So over the last hundred years or so the amount of rain falling hasn't really changed that significantly, but the amount of flash flooding has increased. Water that usually would have been absorbed in ground upstream from towns doesn't, so comes into town where it also isn't absorbed, and downstream from the town it also isn't getting absorbed quick enough, so it backs-up into the towns...
Some very brave (or crazy) souls took the opportunity to kayak down
Padley Gorge in the heavy rains, it usually wouldn't be passable - if you've been there and seen how steep it is this must have been one hell of an adrenalin rush!!!
[Moderator's note by Barry Zubel: Fixed oversize links as they were stretching the forums out]