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.

Read our report

Plastic is poisoning the ocean

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.

22, 566 debris items collected!

The Marine Debris Tracker allows data collected by citizen scientists to be uploaded to a free open access central database and contribute to scientific research.

Download the Marine Debris Tracker App and select the #OneLess bottle survey list to help us understand the extent and scale of plastic pollution in your local area, with a focus on single-use plastic bottles, to help us track changes over time.

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.

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

Since April 2016, we've collected more than 100,000 single-use plastic bottles from along the Thames.

Water bottles make up nearly 50% of single-use plastic bottles that have been categorised in the Thames.

Significantly more water bottles were counted during the spring and summer months.

Over 95% of all bottles found had their tops still attached (Lesniewski, D et al. 2017).

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.

We've produced a report to provide a snapshot of our current understanding of the extent of plastic bottle pollution in the Thames.

Download the report