I had a chat with a man in orange hi-vis this afternoon, as I was thwarted by an extremely closed road (damn you HS2). I explained that, as a cyclist, it's usually worth continuing past road closed signs to have a look, because the majority of the time you can wheel your bike past the obstruction. He told me that "ROAD CLOSED" just means to motor vehicles, and the "NO THROUGH ROAD" sign means it's blocked for everyone.
I'd never heard of that before. I always assumed that the white on red "NO THROUGH ROAD" sign was just a temporary version of *googles* the Diagram 816 one, which is clearly for vehicular traffic (with an optional exception for cyclists), not pedestrians.
Can anyone provide a reference? Google is failing me...