It only really snows in the South of England for about two weeks of the year - it's cheaper to shut down for that time than to invest in snowploughs, chains etc. (just as we don't bother installing air conditioning for the two weeks of hot weather we get in summer).

The people who can drive in snow/ice usually learned in Scotland and Wales where they had the chance to practice (and they do have snowploughs and grit).

The roads are not the problem - it's the ungritted pavements where there's a dusting of snow under solid ice that lead to the most accidents.