The film Harmony: A New Way of Looking At Our World premiered last night at the first Sundance London film festival at the O2 Arena, with introductions by the Prince and the actor Robert Redford, a keen environmentalist and the founder of the original Sundance festival in Utah.

The prince said he was “enormously touched and honoured”, not just because Redford had earlier hailed him as “incredible” and invited him to screen Harmony, but because he had brought Sundance to the UK capital. “I think we owe him a huge debt of gratitude for that,” he said.

Harmony, narrated by and starring the prince, tells how he has worked with environmental campaigners, government and business leaders and visionaries to address ecological and economic problems. The film, which comes two decades after he made an earlier environmental documentary, also spotlights his hopes for a more sustainable, spiritual and harmonious relationship with the planet.

The prince introduced the film, made by Stuart Sender and Julie Bergman Sender, and based on the book of the same name that he co-wrote with Tony Juniper and Ian Skelly, to an audience of cinema-goers and invited guests at the O2 Arena.

Prince Charles said: “I tried to indicate here and there that there are other ways of operating. There are alternatives, there are holistic integrated ways, more balanced ways, more harmonious ways of devising the way we interact with the world for the future. It isn’t impossible, we made changes in the past when we need to. Now is the time I think, ladies and gentlemen to do so.”

He said resources were running out at a rapid rate, but he stressed that changes can still be made. “Somehow, over the last 250 years or so, we have decided we can operate outside of the bounds that nature sets, without having to pay a penalty for that. All we wanted to do with this film is to show people that there is, perhaps, another way of looking at things now. We have carried on in a 19th-century approach to the way we operate for too long. We are now discovering that there are some limitations and we need to look again.”

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Saturday night’s encounter between the prince and Redford was one of several in recent years, highlighting what the Hollywood veteran called a “common, shared feeling about the importance of our environment and sustainability that has been going on for years and years”.

Redford told the audience their shared concern “has been manifested by action. What Prince Charles has done to commit to that ideal is just incredible.”

He added: “I think he has been ahead of the curve – he has been way ahead. And I know what that feeling is, to be ahead of the curve and castigated for it. It is our collective responsibility to do whatever we can to maintain sustainability. The Prince of Wales and I share a dedication to preserving the environment and to identifying innovative and yet realistic ways to do so. This important film showcases his diligence, passion and achievement which include his efforts to amplify the work of social innovators on the front lines of change the world over.”

Stuart Sender said of the premiere: “It doesn’t really get any better than to have the Prince of Wales and Robert Redford here to introduce this film. We hope it does justice to the prince’s vision of a different way of looking at the world. These are two men who are real groundbreakers and have been ahead of the curve on a lot of issues, about preserving the environment, being outspoken and making sure people who don’t have a voice get heard.”

The Prince addressed a range of environmental issues in the film, including wind power, the destruction of the Great Bear Rainforest in British Columbia, Canada, the benefits of organic farming and the impact of globalisation on parts of rural India, where a growing number of farmers are alleged to be committing suicide after losing their businesses to the spread of industrial farming.