Either you are saying I'm lying about the whole thing, or that pushing on the brake pedal to no effect does not constitute brake failure. Let me remind you that I had successfully used the brakes to slow down all along that road for about 1 mile, including a full stop to pass oncoming traffic, and the whole road is in that condition (no better or worse). Moreover, the car in front had no problems stopping where I lost control.
I kind of wish I hand't posted the photos of the road. It is not covered in mud/leaves/loose stones, and it is not icy. It's just brown coloured. Have you not ever seen a brown coloured road? We have them down here - the colour of the chippings they use to make the surface is in fact light brown. Moreover that is the most common condition of roads in Cornwall, and I've driven on such roads almost exclusively in the 3 months I've had the car. We don't have a lot of A roads down here. If you look at the part of the road where the tyres naturally sit, it's is black(er) and merely wet.
Anyway, people will draw their own conclusions. I guess some people will say it's my fault, for whatever reason. Already had one person say it's "user error". The only thing I could have done differently is use the handbrake.