Nuala Gathercole Lam, from Extinction Rebellion, said: “We ask the fashion industry, who do you want to listen to, the youth and the future, or the words of our current Prime Minister, whose Government is criminally neglecting the UK’s agreed responsibilities under the Paris agreement in the face of the ecological emergency?
“Now it is time for the fashion industry to hear the call of the youth.”
Protester Lucas Spencer, 17, who travelled to London from Leeds, said: “I feel like it’s everyone’s problem.
“The world is being killed, we know it is, it’s not just dying, there are people killing it and if nobody speaks about it nothing is going to change.
“The fashion industry creates a lot of pollution and the chemicals they use create a lot of waste.”
Leaflets handed out by the group said the protest was a campaign against “the catastrophic consequences of inaction”.
Fashion fans at the show also said they supported an end to “fast fashion” and throwaway culture.
Speaking outside the main venue, Tatiana Phillips, 34, a personal stylist visiting the show, said: “I’m sure there should be something done, there’s a reason, but I don’t think they should go crazy about it.
“Just yesterday at the festival and today they have been talking about sustainable fashion and how it’s important to move that way.”
Student Holly Cudby, 21, who was also visiting, added: “I think it does need to be more sustainable, fast fashion, even though I buy into it.”