Once in the ocean, plastic remains there for hundreds – if not thousands – of years, killing marine creatures, spoiling our coastlines, and damaging livelihoods. It places added pressure on ocean ecosystems that are already stressed by the impact of human activity.
The ocean supports all life on Earth, and its health is inseparable from our own. It provides us with half the oxygen we breathe and supports the livelihoods of over three billion people worldwide.
Yet a steady stream of plastic is polluting our ocean and adding pressure on ocean ecosystems that are already stressed by the impact of human activity.
Since 2016, we’ve been working with Thames21 to better understand the scale of London’s plastic bottle problem by conducting bottle counts along the Thames.
In April 2018, we developed our approach to include fortnightly bottle counts focusing on five sites along the Thames; Hammersmith, Fulham, Battersea, City of London and Greenwich.
Plastic is poisoning the ocean


Plastic pollution in London
London is a coastal city, directly connected to the ocean by the River Thames. Just as the Thames is the major artery which continues to give life to this great city, the ocean is its heart, sending water, oxygen, clean air, fish, nutrients and weather along the river to make the city habitable and healthy.
Sadly, the Thames is contaminated with single-use plastic and could potentially be transporting London’s single-use plastic back out to the ocean, ultimately threatening marine creatures, spoiling our coastlines, and damaging livelihoods.
- Plastic drink bottles and their lids are one of the top ten items found in the Thames.
- 80% of litter in the Thames is single-use plastic.
- A quarter of fish in the Thames Estuary have eaten plastic.
- The Thames has the second highest levels of microplastics in a study of 13 UK rivers.

Monitoring London's plastic bottle problem
A team of dedicated citizen scientists from the Thames21 River Watch programme collect bottles from the Thames foreshore, count them and sort them into four categories:
- Water bottles
- Flavoured drinks bottles
- Milk bottles
- Unknown, for any bottles where it was not possible to determine the type


Key findings so far
While we are beginning to record fewer bottles during our clean-ups, further research is needed to help us fill in the gaps, accurately establish trends over time and better understand the movement of plastic bottles in the Thames.