|Taking The Lane|
"Riding in an assertive position in the middle of the lane is recommended as safe practice in certain situations – but it can provoke hostile reactions from other road users. Ask any urban cyclist about "taking the lane", and even if they haven't heard of the term, they have probably done it. Although widely regarded as safe practice, this often gets negative responses from other road users."The full article is here, but my view is this - Bearing in mind that 'taking the lane' is recommended by Bikeability, (because cyclists are safest where they can see the road and be seen) I tend to do this a lot, but I pull over when I feel that it is safe (in my judgment) for a vehicle to pass.
I'd be a little more loath to give more room to vehicles if they gave me more room - I demand 1.2 metres of space by the side of the road (roughly the width of a cycle lane) and if I don't get it - I'll take the whole damn road.