A whole movement is much more than one person or organisation. In 1971, when a group of friends decided to sail out to protest against nuclear testing in Alaska they unwittingly started something that would snowball into one of the largest modern activist movements. What Bob Hunter and a small group of like-minded people began in Vancouver ended up with the formation of Greenpeace, and ultimately the environmental movement.

Jerry Rothwell’s new documentary, How To Change The World, uses archive footage and interviews with the founders to tell the story of how a common cause brought them together, started the ecological movement and ultimately lead to in-fighting and recriminations. Most of the disputes boiled down to methods, with the age-old argument that split The Civil Rights Movement being key.

How To Change The World is a fascinating insight into how a small ripple can lead to a huge wave, with Greenpeace now a household name. Whilst Rothwell investigates the roots of the environmental movement, it’s clear that the influence of Hunter is key. The former journalist was a reluctant leader, taking the reigns through necessity rather than desire. In the end, the arguments boiled down to idealism vs pragmatism and the organisation and movement became too large and unwieldy for them to control.

How To Change The World is out in cinemas on 11 September. There will be a nationwide satellite Q&A screening on Wednesday. To find one near you, visit the website.