I cycled thousands of miles a year for over ten years (6000 miles in 1993 alone), and my golden rule was that I owned the lane I was in. I decided when it was safe for someone to overtake (most of the time it was, I'd make room and I would never pig-headedly hold anyone up unnecessarily). It isn't safe for cyclists to ride in the gutter. There are grids and all kinds of debris and there is no escape room. When cycling uphill on a main road, if a line builds up behind you, stop and let them pass.