Then it is not a mandatory cycle lane (i.e. it is not mandatory for motorists to keep out of it if there are no cyclists using it). I think the sign is perhaps acknowledgement (albeit it unintentional) that most motorists have little understanding of the Highway Code and roads law...
I agree with you there Regulator.
As someone who got a driving licence (errr... ahem) years ago, I doubt that I have ever formally been taught about:
*) zig-zags around pedestrian crossings
*) advanced stop lines for cyclists
*) different markings for cycle lanes
*) I'll throw in my own bugbear here - the rule about giving way to people crossign the road when you turn into a minor road
Back in the day there were Public Information Films which updated your knowledge on these things - indeed if I'm not wrong there was one on the zig-zag lines. These days Public Information Films none - and you would think with the advent of YouTube then you could combine both broadcast and internet information films.
However, another point if I may. Today's road environment in cities is extraordanarily cluttered with road markings and signs.
I doubt if there is a single stretch of major road near me in London which has a continuous stretch of single white lines.
You have bus lanes, traffic lights, pedestrian crossings, one way systems, left turn only lanes - the list goes on.
I genuinely do think this makes driving a lot more difficult.
Don't get me wrong - I'm not saying bus lanes are a bad idea, jsut that there is a huge amount of visual clutter.
I find it is a lot easier to drive along (say) the Embankment which is a route I know well - so I know when to bear right or left to get in the correct lane.
On unknows roads in London I'm a lot more anxious.
I don't have the answer, but the point I'm trying to get across is - do we really need all this white paint, and don't get me started on the blue paitn of cycle superhighways.
ps. the new CS route on the Embankment going past Millbank has wide blue lanes - with solid white lines.
How many drivers know that this is a mandatory lane and they must not drive there? How many would honour it even if they know?