You're not on Plusnet are you, Roger? They are usually good, but ours has been acting up at intervals recently, and there was a thread about it on another forum. Resetting my router has sometimes fixed it for a while.
Apart from that, according to the 'experts' there seems to be some Google bawlocks going on. I've noticed that some cgi scripts which Google use to monitor internet activity (yes including that sort of activity) are taking an age to run at the moment. Nikon Rumours for example, is particularly slow and when it hangs, the info. bar indicates cgi loading. No doubt it will all sort itself out eventually.