Our story

The ocean supports all life on Earth and its health is inseparable from our own. It provides us with half the oxygen we breathe, supports the livelihoods of billions of people worldwide, and is home to nearly 200,000 identified species.

Yet, it is currently under threat – from plastic pollution. Eight million tonnes of plastic enters the ocean every year, with rivers playing a key role in transporting plastic into the ocean.

#OneLess was established in 2016 to reduce London’s single-use plastic footprint and tackle ocean plastic pollution at source. Our aim is to change the way people in London access and drink water, ending the reign of single-use plastic water bottles and facilitating a transition to more sustainable approaches, focused on reusing and refilling. When we started in 2016, Londoners bought over a billion single-use plastic water bottles every year, with many of these making their way into the River Thames and potentially flowing out to the ocean.

We take a uniquely collaborative and systemic approach, working with a rapidly growing movement of pioneering individuals, communities, businesses, NGOs, and policymakers to find and implement solutions to transform the system of hydration in London.

How we work


#OneLess is inclusive and collaborative. We place great emphasis on working with others, building powerful partnerships, and sharing what we learn.


We use a holistic systems change approach to understand the problem and to help us strategically choose impactful activities and interventions.


We believe that in order to properly protect the ocean, people need to develop an understanding and appreciation of the value it provides.


We place great emphasis on fostering a culture where monitoring, evaluation and learning is paramount and where best practice is shared.

The #OneLess team

#OneLess is led by a successful collaborative partnership between four organisations: the Zoological Society of London, Forum for the Future, the International Programme on the State of the Ocean, and the Thames Estuary Partnership. Together, we combine backgrounds and expertise in science, policy, system change, sustainable estuarine management, and communication. We are all are members of the Marine CoLABoration, a group of marine NGOs working together to put value at the heart of solutions for the ocean, which initially launched #OneLess as an experiment in 2016.


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Sign up to receive further information about #OneLess from the Zoological Society of London (ZSL).

The #OneLess campaign is hosted by the Zoological Society of London (ZSL) working alongside the other #OneLess partners. ZSL is an international conservation charity which is working for a world where wildlife thrives.


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Our supporters

#OneLess is supported by the Calouste Gulbenkian Foundation (UK Branch) and the Oak Foundation, with additional time and resources contributed by the lead groups. It was inspired by the work of Project Ocean, the partnership between Selfridges and ZSL, which began tackling ocean plastic in 2015. Selfridges is one of the pioneers in this movement and continues to support #OneLess today.