Many well-intentioned people who advocate paying extra for products bought from developing countries are simultaneously supporters of buying as much as possible from local producers. Take the author of Doing the Right Thing, a blog written by a Brit who is "striving to be good", who writes under the pseudonym Birdy Chirp:

My mother came to visit last weekend and as ever we were talking about ethical issues. Sometimes I think we compete to see who's most ethical - she usually wins as she's better at not shopping than me. I occasionally win on the boycott stakes...

Anyhoo - I opened some English wine for dinner (no air miles, 15 nil to The Chirp) when Mum told me that she'd had some really bad Fair Trade wine. Now I haven't tried Fair Trade wine - but I'm a huge fan of Fair Trade. I'm not a great economist - I can barely spell it, frankly. But Mum said she'd been told - by a Cambridge economics graduate - that Fair Trade wasn't the answer. In fact this person actively boycotts Fair Trade...

I really don't know whether or not Fair Trade will solve all the economic problems there are in the world. I suspect that that's more down to the Big Cheeses. But if you're going to buy a banana, or some coffee, or an avocado anyway isn't it better to buy Fair Trade? Person to person - someone has had a fair price and good conditions, and I get to win. Is that an example of thinking globally and acting locally? What do you all think?

This is a person who has a clear desire to be ethical. But here he advocates Fairtrade wine, so as to help producers in poorer countries, while simultaneously advocating buying English wine. There's a problem. Buying English wine doesn't help poorer countries, so producers in poorer countries are not going to like this Brit's purchase. On the other hand, buying from overseas producers may well have a higher environmental footprint than buying from a more local English producer.

English wine is not exactly world-renowned, so I suspect that the author is buying it simply because it is locally produced. In other words, it may be that he is sacrificing both cost and quality in order to buy from an English producer. That said, I concede that sometimes the location of the producer can count as part of what we mean by quality. For example, on holiday in Provence a few years back, I brought back with me some (excellent) local Provence wine and honey. To me, the fact that they were made in Provence was an essential factor. If I were to go on holiday in Colston Basset in England, the home of the Stilton cheese, you can bet that I wouldn't come away with any (French) Camembert.

So should our ethical consumer always buy from developing countries? Certainly, if his desire is to help lift the living standards elsewhere in the world, then buying wine from poorer countries would seem a better idea than buying the English product.

But always buying from developing countries also has its problems. If we buy from a poor country regardless of cost or quality, in an attempt to be ethical, we might well send the wrong market signals. It might be best to just buy according to cost and quality and let producers rise to the challenge.

Alex Singleton is president of the Globalisation Institute, an international development think tank.