Lambeth Bridge has just been resurfaced, and they've re-marked the bridge so it's actually rather better for cyclists. So, credit where credit's due, TfL have done two things right: 1. they've taken the opportunity of the bridge resurfacing to consider whether the layout could be improved (rather than re-marking it as it was and then later having to change it); 2. they've seemingly taken some notice of what cyclists are saying.
The main change is the northbound carriageway is wider, and the cycle lane is also wider. This has two effects: the northbound motor traffic tends to stay further away from the cycle lane, and there is more room in the lane. You can just about overtake other cyclists within the lane now.
Southbound they've removed the cycle lane, but I never found that much use anyway - there's still a bus lane and there's usually not much southbound traffic anyway so taxis can give you a wide berth.
Below you can see how it used to be:
squashed under a left-turning HGV. However, to be fair, all they've done is resurfaced the bridge, and fixing the approach to the bridge will require some re-engineering of islands and pavements. And of course both the southern and northern roundabouts are problematic. So we're left with a reasonable-quality link between two very dangerous and intimidating junctions. The fact that I'm highlighting this as an welcome and unexpected improvement is indicative of how low the standard of progress is elsewhere, for example on Blackfriars Bridge, where the environment is actually being made worse for cycling.