"Barclays Cycle Superhighways are new cycle routes that run into central London from outer London to provide cyclists with safer, faster and more direct journeys into the city. The new routes are clearly marked and easy to follow. There are new signs and road markings, as well as information about journey times and links to other cycle routes. Brand new cycle lanes and bold road markings will increase awareness among other road users, and make it clear that the route is used by many cyclists." (see here for more information from TfL)
So, right, there are no actual rules. It's not like a bus lane where there are times when other vehicles aren't allowed on the blue bit, it's just there for "awareness" and route finding. WTF? So we're just lucky that other road users seem to mostly stay out of it. Mostly. When it suits them. And it seems to sort of mostly work in the morning, and earlyish in the evening, but in the middle of the day or after about 6pm, it utterly does not work in the slightest. Delivery vans, parked cars etc. park in the lane and either simply obstruct it completely or open doors into traffic without checking for oncoming vehicles regardless of the amount of flashing, bright lights, fluorescent clothing, reflectors... Oi! Boris! Sort it out!