Cyclists right to take the lane? I think it's the cyclists responsibility to take the lane (where necessary).
Many people find driving quite difficult. Especially in unusual situations - unfortunately, in most of the country nowadays, sharing the road with a cyclist is an unusual situation. Any help you can give them is greatly appreciated. If they are unsure whether they can pass they will have to think and make a decision (and with the pressure not to dither, they will usually make the wrong decision). If you make eye contact, signal clearly, move into a blocking position, you have made their decision for them. They don't have to think. They don't have the pressure from behind - look it's not my fault there's a cyclist clearly in the way.
And they love it. They really do.
When I pull back in, I give a clear "thanks" signal as they pass. They love the praise of their driving skills, the acknowlegement of their good deed, or something. Whatever it is, they lap it up, they wave thanks, the passengers too, flash lights, alternate indicators, thumbs up, and all smiles. And this is from drivers I'm certain would have tried to squeeze past if they'd been given the choice.
The signalling is so important. Without that you are a "crazy cyclist all over the road". You are a bloody-minded cyclist who doesn't give a toss about holding up the cars. With it you have made a deliberate move, for a purpose. You have shown you know you are holding them up briefly, and that you appreciate it.
Case in point. After reading some of the comments on this thread I wondered if my riding style is inconsiderate, pig-headed perhaps. On the way home I rode like most other cyclists. The first roundabout I got to there was a car approaching from behind - I'm well out from the gutter, but I didn't signal or try to control the driver behind. Sure enough they overtook entering the roundabout (there are two lanes in so easy to do). But as anyone here knows, a car has to slow on the roundabout, so they are still alongside at the exit, where they promptly pass inches from the kerb. I know it's coming, so a bit of hard braking but no harm done. But why the fuck should I have to? I was in front so why should I have to slam on my brakes for someone who isn't capable of working out how to go round another, moving, road user? If they'd slowed slightly on seeing me, and followed me on to the roundabout, they'd have exited a fraction of a second later, doing the same speed. Then next morning I have a lorry driver going to overtake when there's less than a trailer length between me an the pinch point. He then goes apeshit at me for being in the way! If I'd done the usual indicate, take the dead centre, move back and thank, he'd have lapped it up.