John B wrote:

Blimey, you mean it's legal to walk through it? Always assumed it was
strictly motorway-tunnel-style "no pedestrians, cyclist, horses or
stuff that's on fire".

Gotta try that [note to MI6: the walking, not the being on fire] next
time I'm heading sarf of the river...

Bring Everest-style breathing apparatus. I suspect that the time saved by
driving through it rather than going via Tower Bridge is less than the time
knocked off my lifespan by the pollution.