Well it obviously isn't lit *enough*, is it.
The night sky is lit, by the moon. But it isn't lit enough to cycle without lights. That isn't the council's fault!
The fact is you went careering down a blind duck path little more than 2 feet wide at breakneck speed into the pitch blackness without lights, heard a quacking noise ahead and instead of braking to spare the duck, you decided to accelerate and mow it down, but unfortunately it wasn't a duck but a large goose and in running it over it caused you to fall off. Due to fatness, you then became wedged in the railing.
You then decided to concoct a cock and bull story about it being a pothole that caused you to fall off, in order to blame the council.
You are hoping you are going to be believed because conveniently no-one else was in the tunnel to witness this incident.
I for one however can see through this little ruse, because the fact is that you have ridden through this tunnel countless times before so if there was a pothole, you would have known where it was.
If you'd cycled on the road this wouldn't have happened!