Thirty miles off the southern tip of Sri Lanka. I remember vividly a tiny breeze tickling the surface of the Indian Ocean; the heat radiating relentlessly. After three weeks on the research vessel most of the film crew had developed deep tans from working in the sun. We had spent hundreds of hours travelling up and down the coast gazing out to sea in the hope of spotting our elusive quarry. So far, all we had for our efforts was just one ghostly shot, filmed from a distance, which wasn’t enough for our purposes. Our aim was to be the first to film the largest animal on the planet under water – the blue whale. We also wanted to conduct scientific research to see if blue whales had been exposed to plastic through their diet and location. At distance, we had seen them blow almost every day. But these animals can spend 30 minutes under water and reach speeds of 20 knots. We simply couldn’t keep up. After a massive effort, we were forced to finally turn around and make our way back to Galle. We had to be in port in 4 hours to make our customs check.

It felt like a terrible defeat. We had moved 12 film crew and a ton of equipment half way around the world to a difficult location. We had spent tens of thousands of dollars. And we had battled bureaucratic and corrupt government officials who almost scuppered the trip before it began because they wanted money before they’d let us leave port. But something at the back of my mind refused to give up. We were still on the water, we still had a few hours of motoring and that meant we still had a chance of an encounter, no matter how slim that now appeared.

Within half an hour of turning around, I heard magical words: “BLOW”. I rushed to port side and saw in the distance not one blow, but two. What was different about this encounter was the lack of a tell-tail sign of fluking, which is when the whales point their snouts vertically and begin a deep dive to feed or to just disappear. I marshalled the on-board camera team to set up and our dive crew and cinematographers were already putting the Red cinematic 4k resolution cameras in the heavy Gates underwater housings. We jumped in the pursuit boat and we cautiously headed towards the lingering behemoths. About 50 metres from our target all three camera teams lifted in to the water and began cautiously finning towards the whales. There were not two, but an entire group, and what appeared to be a juvenile. These weren’t true blues, they were pygmy blue whales, a slightly smaller cousin of true blues, but blues none-the-less.

Normally, I’d direct filming from the boat, but this moment was one I had waited all of my life for. I donned my fins and mask and headed for the action. Beneath the waves, the family of pygmy blue whales revealed themselves. They appeared to be resting. This was our moment of truth. Would they hang around and let us film or would they show their normally shy sides and slip away? Fortunately, the juvenile was as curious about us as we were of his family. Almost 15 metres in length (just over half the size of his parents), the juvenile turned towards John, one of our cinematographers, dived beneath him and gently moved towards him to take a better look at what he was doing. I couldn’t believe our luck. After all this time and effort, with just hours to spare, we had a whale performing for us. It was a significant moment. We were the first to film pygmy blue whales underwater, and the first to film a juvenile. As these thoughts were racing through my head I could see through the clear indigo-blue water a large, blue/grey object ascending through the god rays right beneath me. It was the juvenile. Clearly, he wanted to engage. I took a deep breath and began to fin towards the whale. As I did, the calf rolled over on its back and showed me its stomach. Without warning a massive cloud of bright, chunky orange gunk flushed out of its bowels. As I fought to see my way through the cloud and reach the surface it dawned on me that I had just been pooed on by one of the rarest creatures on the planet. I surfaced to see stills photographer David Jones laughing uncontrollably. He’d also been caught in the poonami. I grabbed a bucket from the tender and began to scoop up the large, extremely smelly chunks of digested krill waste. I took it to our cetacean expert, Lindsay Porter, who declared that as far as she knew I was the first person to be pooed on by a blue whale. The specimen I collected became very important in the scientific research we conducted on the whales, providing information on DNA, toxicology, diet and other information not normally available to the scientists.

That shoot was the first of multiple shoots we did over the next five years in 20 locations around the world for the documentary feature film, A Plastic Ocean. The feature film, the brain child of producer Jo Ruxton and executive producer Sonjia Norman, investigates the global problem of plastic pollution in the world’s oceans, the damage it’s causing to marine life and how it’s coming back up the food chain to poison the species that put it there in the first place – humans. The audience follows an investigative trail, led by myself and world record-holding free diver, Tanya Streeter, as we travel the world’s oceans to see if the plastic pollution problem in the north pacific gyre exists elsewhere on the planet. The results of our investigation are mind blowing, unexpected, sad, depressing, and revealing. But ultimately, as we look at solutions, it is also hopeful.

While the whale sequence made the film, my personal encounter with the juvenile was relegated to the cutting room floor. But it remains one of the most vivid memories I have of that very first, inspiring shoot and the realisation of my lifelong ambition to meet a blue whale. And as I sit in the audio engineer’s studio in Los Angeles, putting the final sound mix to the film, I cannot help but reflect on how A Plastic Ocean has been an incredible journey for everyone involved. One of our wonderful supporters, Sir David Attenborough, who was kind enough to take part in filming, has described A Plastic Ocean as “one of the most important films of our time.” Given the scale of this unfolding environmental catastrophe, his assessment is powerful. We have learned much on this journey and we want as many people as possible to understand this issue and to be motivated to force society to change its attitude to single use plastic. As Dr Sylvia Earle says: “With knowing comes caring. But if you don’t know, you can’t care.”