According to this article, you give way to the right on roundabouts. I am not aware of this, nor how it could work - this is what used to happen, with more and more cars coming onto the roundabout, and traffic snarling up! If anything, you give way to the left on a roundabout, i.e. those vehicles already on the roundabout have priority. Typically, once on the roundabout, you have right of way over vehicles waiting to join the roundabout - they have a give-way line to cross. Please tell me what I've missed!
Ian Dudley (in La Sarthe)