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A steady stream of plastic is polluting our ocean and putting pressure on ocean ecosystems that are already stressed by the impact of human activity.

Applying solutions and interventions that have been informed by science has been crucial to our approach.

Thames Bottle Monitoring Programme

London is a coastal city, directly connected to the ocean by the River Thames. Just as the Thames is the major artery that 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.

Since 2016, we’ve been working with Thames21 and their dedicated team of citizen scientists to better understand the scale of London’s plastic bottle problem by conducting regular bottle counts along the Tidal 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.

Key findings

Between 2016 and 2021, #OneLess and Thames21 volunteers collected more than 135,000 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).

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

Read our report

The Marine Debris Tracker

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.