There is an odd moment when shopping, with which most readers will probably be familiar. It's that second when you're standing in Tesco/Primark/Asda fingering (for example) a £20 sequinned top, and into your head pops the image of an exhausted woman, head bent, sewing on each of those sequins. The glitter of the top dims a little.
You might put it back. Or you might reassure yourself that we are no longer in the Victorian era of labour sweatshops - don't most companies these days sign up to some ethical code or other? - and head for the till.
Well, there is an ethical code. It's called the Ethical Trading Initiative (ETI). But as the past few months have shown there are serious doubts as to how much this means. In October an undercover investigation for Channel 4 turned up evidence that suppliers for Tesco - one of the ETI's founding members - were using child labour, an allegation that Tesco refutes.
Then last week anti-poverty campaigners at War on Want released a report about the conditions and pay of Bangladeshi workers supplying Asda, Primark (also ETI members) and Tesco. It did not paint a pretty picture. Again, all three companies vigorously defended their ethical position.

Many anti-poverty campaigners have nice things to say about the ETI (although one woman laughs when I mention it and someone else sighs). But there are some serious flaws in the set-up, and these are only going to become more problematic.

The ETI lives and dies by its admirable "base code", a list of fundamental principles such as the right to a living wage (ie, a wage on which you can support yourself and your family), the right to safe, hygienic working conditions and the abhorrence of child labour. But one of the biggest problems is that, although any companies signing up to the ETI must sign up to the base code, they are not committing themselves to living by those principles, only to working towards them. There is a big difference.

Companies that sign up are using their membership as a sort of endorsement, as if it guarantees something in the way the Soil Association logo or the Fairtrade mark do.

Take Primark: it resisted signing up to the initiative until this year. Then the ETI released a joyful press release announcing that the chain was planning to "provide till notices for interested customers that set out the company's commitment to continually improving working conditions in its suppliers' factories". (So already Primark was visualising its ETI membership as in-store advertising for its ethical credentials.)

Then, when Primark's name came up in the War on Want report, its response - and implied defence - was that "as members of the Ethical Trading Initiative we are fully committed to the campaign to improve working standards in Bangladesh". The ETI becomes a sort of shield.

And what happens if you are proven to have come in under par? The ETI does not seem to deal in public rebukes or summary ejections. There is a procedure should it be necessary to remove a company from the list, but the head of communications at the ETI cannot remember if any company has ever been chucked out.

In a brave exercise this year the ETI got an independent organisation to measure whether it had actually achieved anything. In some ways the results could be interpreted positively: major improvements in areas such as health and safety and working hours by ETI companies were recorded. But looked at more harshly, the results might be perceived less favourably: with 90 categories, there were major improvements in only 12, after 10 years of work.

Anti-poverty worker Deborah Doane of Core, the Corporate Responsibility Coalition, thinks that the ETI was important when it started up, as a forum for people to talk about all these things. "But it has focused too much on the voluntary bit - the pat on the back mechanism - without looking at what you need to change this picture. The companies which signed up haven't done as much as they should."

Some companies really are trying to improve, but others are proving to be brilliant at what are seen as cosmetic ethical initiatives - using organic cotton, starting up Fairtrade T-shirt ranges - all of which create an undeserved rosy glow around the industry.

In fact, conditions are worsening for many workers in Bangladesh, China and other developing countries, and more bad news will be emerging over the next few months.

Our obsession with cheap, trendy clothes means that retailers push suppliers to offer them lower and lower prices (something similar happens in the food industry). One supplier was quoted in the independent report on the ETI as saying that "they struggled to meet this element of the base code [non-excessive working hours] due to the need to meet tight production deadlines with short lead times". It is only fair to point out that even if the ETI is ludicrously weak, in the end it is the companies that need to take action.

And campaigners in this area seem to agree that the only way to get the big companies to change at this point is regulation and legislation. If we are depending just on voluntary codes and self-regulation, it is going to be slow progress.

For now, working conditions are still sunk in the 19th century, except that the sweatshops are that much further away.

So is there any way of ensuring that you are not supporting sweatshop labour?

For a start, you can support any ethical clothing initiatives by the big companies; that's what will encourage them to keep going. Besides that, buy from small companies, buy second-hand clothes, apply pressure yourself . . . not much of an answer, really. Especially if you're a garment worker in Bangladesh.