Two of the biggest names in British fashion are accused of failing to live up to their fine words on animal rights and the environment.

Stella McCartney is a vocal supporter of anti-fur campaigns, while Vivienne Westwood crusades against climate change. But while they may score highly on Paris's catwalks, they are criticised in a guide showing that luxury fashion brands fail to take corporate social responsibility seriously.

There's no doubt that McCartney shuns fur in her designs. But the same cannot be said for the company that owns her label. For Gucci (part of the PPR group) allows and promotes the use of fur. And it is accused by Ethical Consumer magazine of being unable to demonstrate that it has an environmental or supply-chain policy to guard against damaging the environment or exploiting workers. And Westwood's environmental credentials are dented by her company not appearing to have a formal policy to reduce its carbon footprint.

Bryony Moore, the guide's author, said: "McCartney and Westwood are held up as ethical heroes. While they might be talking the talk, they're failing to walk the walk. Fans will be severely disappointed to learn their ethics are only skin deep. They are far from the only brands performing badly. Most make no mention of their environmental and social impacts."

The 30 luxury brands in the guide are scored against 15 indicators on human rights, political lobbying, the environment and animal welfare. Paul Smith, Moschino and Jean Paul Gaultier fare best, coming joint top with seven out of 20. But Vivienne Westwood, owned by Latimo SA, lags behind with five-and-a-half and Stella McCartney is given two out of 20 – only beaten to the bottom by brands owned by LVMH/Christian Dior SA – which get just one-and-a-half.

A Vivienne Westwood spokeswoman said: "We are committed to changing the way we do business to minimise our impact on the environment," but added that "not all our products are produced with the environment in mind".

A spokesman for PPR, which launched a drive earlier this year to "implement more sustainable business practices", accused the guide of containing inaccuracies.

Additional reporting by Paul Bignell