Why is commuting excluded from my car insurance?

I thought I was covered under 'social, domestic and pleasure'

When renewing my car insurance, I noticed that using the car for commuting was excluded from "social, domestic and pleasure". I questioned this, and was charged just £1 a year more to include commuting. PH, Norwich

It used to be included automatically with social, domestic and pleasure cover. Be aware that even driving to the station counts as commuting. Non-commuters now pay less because they make fewer claims as, generally, they avoid the rush hour.

The Observer, Friday 11 November 2011