I used to live there and visit the place fairly frequently (and I KNOW it’s the “Daily Express”), but dimness of this magnitude never ceases to amaze me.
Grit is small chips of granite or similar rock. It melts at around 126o Celcius. Cold does nothing to it. If you put grit on your walkway, it gives your shoes grip and you can walk on frozen snow with ease.
Even at -20 Celcius
Salt works in the single digit minus range.
Salt is not grit.