Comment at 19.42 on this story in the Daily Mail, two days ago: 'It's time we started abusing smokers physically.'
After writing to the Daily Mail about this, I went to a local cop shop this morning (just out of curiosity), with the offending words. Their advice was that it wasn't a police matter, and that the matter should be reported to the Daily Mail. I asked under what circumstances it would be a police matter (for example whether it would be a police matter if directed at another specific group of people) and the officer on duty said each case depended on the exact wording. She said I had done the right thing by complaining to the Daily Mail in this instance, and would be welcome to check any other instance with the police.
So that's what to do: use the feedback form if you want to make your displeasure known. Or letter or any other form of complaint that you can.
