It now seems to have added wrongness/vagueness....
In front lamp section:
It gives
but mentions nothing about the effect of lens/reflector focusing* whether measured lumens or theoretical lumens etcfor a guide, 1 candela approximates to 12 lumens
* which of course mean a central 4 cd spot/letterbox can be reached with a 7lumen filament bulb.....
In the Rear Lamp section it adds
You might have noticed that rear bike lights tend to have much lower lumen outputs than front lights. Firstly, is because we're unlikely to want to see where we're going with the rear light but it is also because our eyes react differently to red and white lights; to our eyes, a 50 lumen rear light has similar brightness as a 200 lumen front light
Errr, this seems to be a confusion of the fact that placing a red filter over the old fashioned cycle filament bulb(white) reduced the light to 25% of the unfiltered light.... And the lumens/candelas measurements mean the same perceived brightness for different colours (in daylight: in low light your eye finds blue brighter that but this is not accounted for in such values, and this line is comparing white to red.....).
In the Seriously Reduced visibility section following
the line 'It would nevertheless be a good idea to so so!' has been replaced by 'Yes, the law is strange'So even if the cycle has lights fitted and is ridden into a bank of fog, for example, they do not have to be switched on.
In the Additional lamps and reflectors section:
the bit mentioning that one should avoid dazzling other road users has been removed.