Over the next 10 years, after completing a PhD and going on to teach marine biology at Newcastle, Southampton and Plymouth universities, Prof Thompson spent his spare time beach-hopping, often enlisting students to help him gather dozens of sand samples in tinfoil trays.

Thompson’s hypothesis was correct: microplastics result from the lengthy breakdown of larger items, and they will linger for decades more thanks to plastic’s inherent durability, all the while absorbing harmful toxins and pathogens that end up in the bodies of marine animals.

What concerns Thompson is that policymakers may be led astray by much-hyped approaches that are already being used – for instance, hi-tech initiatives to remove plastic from the sea, such as the Ocean Cleanup.

We now know – again, thanks to experiments by Thompson and colleagues – that many biodegradables need controlled industrial conditions to degrade, and can take years to disappear in soil and sea.

“Let’s turn to the solutions, which lie upstream,” he told an audience of delegates from 58 countries, explaining that in order to slow the flowing river of plastic, we first need to narrow its source.

Growing scientific consensus on these and other issues could soon be crucial in guiding nations towards solutions, so as a scientist, Thompson is frustrated that there is no UN-level mechanism to communicate the most up-to-date plastics research to governments.

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