"Poor people" should buy fewer clothes and be more careful about the quality of the garments they buy, according to Dame Vivienne Westwood.
Speaking after her show at London Fashion Week, Dame Vivienne pleaded: "Buy less. Choose well. Make it last. Quality, not quantity. Everybody's buying far too many clothes.
"I mean, I know I'm lucky, I can just take things and borrow them and I'm just okay, but I hate having too many clothes. And I think that poor people should be even more careful.
"It doesn't mean therefore you have to just buy anything cheap. Instead of buying six things, buy one thing that you really like. Don't keep buying just for the sake of it.
"I just think people should invest in the world. Don't invest in fashion, but invest in the world."
The eccentric designer sat among celebrities and fashion journalists in the front row for the show at the German Gymnasium in north London, instead of waiting backstage as usual.
It meant she had pride of place for the dramatic opening, which saw supermodel Lily Cole performing an interpretative dance while wearing a flowing, Grecian-style gown.
Dame Vivienne also urged people to take more of an interest in culture, saying: "The first thing they can do, if they live in a town, is they can go to art galleries.
"Start building different values, where you engage with the past, with the human race."
The Vivienne Westwood Red Label collection for spring/summer 2014 saw models, their faces caked in black and white make-up, wearing the designer's trademark tartan, embellished with oversized corsages.
There were also English country garden prints and t-shirts printed with the phrase: "Climate Revolution", the designer's political and environmental message making its mark on the catwalk.
Those watching included Hollywood actress Anna Kendrick and singer Paloma Faith.
Cole said she had been nervous about her modern dance debut, which she had devised with the help of a friend, but said collaborating with Dame Vivienne was "not even work" as she enjoyed it so much.
"I'm doing it for the love of it... and to try to communicate the values we both believe in," said Cole. "I also did it because it scared me. I've never danced live before. I think it's important to challenge yourself in life."
The Topshop Unique show also attracted celebrities to the front row, with those in attendance including Kate Moss, singer Ellie Goulding and model Pixie Geldof.
Geldof said of the collection: "I like that it's for everybody and it's not snobby. I think it's very good, very British. I don't think it should be exclusive."
Head designer Emma Farrow said she had been inspired by "the ultimate summer", and the idea of "every girl's perfect holiday". Geometric prints, mirror detail and shirt dresses all featured on the catwalk, with a colour palette of azure blue and emerald green.
The five-day trade event, featuring 58 catwalk shows, continues this week.
US designer Tom Ford returns with a show today, while Stella McCartney will display her Adidas collection on tomorrow.
The event is expected to attract more than £100 million in orders, according to the British Fashion Council.