In my column in The Herald today I urge visitors to mind their own business, and not just because Mr McEwan tells us in the same letter that "unfortunately a number of our staff have faced verbal abuse" asking smokers to put it out.

Smokers have become the new public contemptibles, and I believe the motives behind those railing against them are questionable. Those who are disgusted when they find themselves so much as walking past smokers at, say, a hospital are seeking, I say, to inflate their own esteem with their sanctimony and purity. There is, for example, a delicious reward for women who didn't smoke during their pregnancies to be had in being sickened by the sight of pregnant women smoking at hospital.

Many of you will misconstrue what I have written here. I am not in favour of smoking - rather, I believe strongly that smoking should be banned nationally in all public spaces. But people who are addicted smokers are not in hospital to confront their addiction, and public hospitals have no fair right to take advantage of these people's incapacity to try to stop them smoking. And you precious non-smokers who are simply appalled should examine your motives. And if you find all is in order, how about granting me an open examination of your life.

Walking past smokers in the open air at hospital or anywhere else is no worse than walking past people with body odour or, even, wearing perfume. But the impact of smokers on you who are appalled is not what it's about. Rather, it's about you taking an opportunity to put your righteous boot into people who are down and in no position to defend themselves.