Length of habit: about 30 years, with a 10-year gap when she was bringing up children.
Time spent on it: two or three occasions a week.
Cost: about £120 a month.
The habit: "I normally buy grass rather than hash [resin], an ounce costs about £120. I buy it from friends who get it from other friends - I don't know any full-time dealers.
Usually I just have one joint, although at a party I might smoke all evening. I won't take alcohol - they don't go well together. I tend to smoke with friends, at their homes, although at my age there aren't that many who do it any more. Smoking at my home is difficult because I've got teenage children and I don't want them to know: I think they would find it unsettling.
"My eldest child has told me she uses it. I've stressed to her it's only for recreational use, not before lectures or a seminar."
Pros: "It helps me to relax and I love the fact that you can get stoned and not have a hangover the next day. It also makes listening to music blissful. And smoking before going to a dinner party helps me to feel more sociable.
"Cannabis makes me laugh, though I don't get as giggly as I did at the beginning. It can also give me flashes of insight. And if I'm fairly overwrought at the end of the day, it's a wonderful way of getting to sleep, much better than pills."
Cons: "The risk of lung cancer from inhaling the tobacco worries me, which is why I restrict the habit. You do inhale it in a different way so there must be more tar in the lungs. When I've smoked I can forget what I'm talking about in mid-sentence, although I'm always back to normal the next day. It being illegal is a problem, although for me getting caught is very unlikely. But I stress this to the children: if you're caught, you have a conviction for life."