Left hand lanes are becoming unpopular because state of the roads these days. Some parts of M25, A2 and A13 are so worn down from haulage that any smaller car just tramlines in ridges. It doesn't take long for the taught discipline to be forgotten in those confitions. So gradually, over the years, in many parts of south east left hand lane became the uncomfortable "slow lane" for articulated lorries, and the rest moved over to two lane system - middle lane became the left hand lane and right hand lane became the avenue of "me and my audi are late, move away", tailgaters and flashers.
Unless of course we are talking about M6 around moonchester, in which case it's all men for themselves - "it's not your overtaking lane, it's their two undertaking lanes"