The survey, which has been conducted by Ethical Consumer magazine, found that only five high street brands scored 10 or over out of 20 assessing their ethical standards.
Primark was the worst offender, according to the survey, with a score of 2.5. It is followed by Mk One, at 3 points, with Marks & Spencer, Debenhams and Gap filling out the bottom five.
The report is based on data on thousands of different companies, supplied by various environmental and labour activist groups then compiled by Ethical Consumer magazine.
The criteria include the environmental policies of the companies and whether or not they operate in countries with oppressive regimes, including China.
Primark is also hit because it is owned by Wittington Investments, a company that also owns Fortnum & Mason, which sells foie gras, thus incurring a further loss of ethical points.
According to a report in The Independent, Primark defended its record, saying it sourced its clothes from "pretty much the same range of suppliers as everyone else on the high street". The chain could not be reached for comment by Brand Republic at the time of writing.
The findings come as the chain enjoys enormous success -- in part based on its incredibly low prices. Last month, it showed emphatically how it had bucked the high-street downturn by announcing a rise in profits of 30% for the year to September 17, with sales of £1bn. Like-for-like sales for the year were up 17%.
Competition between clothing chains on the British high street is fierce as they compete to offer the lowest prices. Ruth Rosselson, a spokeswoman for Ethical Consumer, said that shoppers must realise that if prices are low, then they are low for a reason.
She added that it was not good enough for companies to say that they are doing their best, calling for independent auditors to check on suppliers.
"There is no fairtrade label for clothing. We want more from retailers than vague statements, we need guarantees that standards are being met," she said.
At the top end of the scale were brands such as Equop, Hug, Gossypium and Bishopston Trading.
The report will be published in the January/February issue of Ethical Consumer, which comes out next week.
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