Why fair trade is fair enough - up to a point

I HAVE a guilty secret. Every time I go to the supermarket, I buy fair-trade bananas. Sometimes I also buy fair-trade coffee. If I'm feeling flush, I'll buy organic produce. Occasionally, I go to the local farmer's shop and buy locally-grown produce, also all organic. There, I've admitted it.

What is there to feel guilty about that? Surely this is what we all should be doing, supporting poor people in third world countries, supporting local farmers and helping to reduce the amount of chemicals poured into the land? Well, I used to think s...