In my way in to town, I use a big roundabout called Colne Bank. Two lanes of traffic approach it from my direction, and there are two lanes on it. The left lane was always a feeder lane for taking the first left turn off the roundabout, so if you wanted to go straight ahead or turn right then you used the right lane.
This is still, in fact, the case. That's not what the directions on the road say, though. Here's a picture of what you see (start at the top of the picture):
So if you want to go straight over, you take the left lane. It tells you this twice. Then, when you reach the roundabout, there's an arrow telling you left turn only and you're fed into the next left turn off the roundabout. Meanwhile, a new lane appears that you should take to go straight ahead, only you can't take it because it appears out of the right lane, not your own lane.
That's Colchester for you...