Skip to main content

To: South West Water, Environment Agency, Marine Management Organisation, Natural England, Duchy of Cornwall, Councillors of the Isles of Scilly, IoS Wildlife Trust and National Landscape.

Give Scilly the Highest Standard of Sewage Treatment

St Mary's, Isles of Scilly
We are calling on: South West Water; the Environment Agency; the Marine Management Organisation; Natural England; the Duchy of Cornwall; the Council of the Isles of Scilly; the Isles of Scilly Wildlife Trust and National Landscape; to permit nothing less than the very best sewage treatment for the Isles of Scilly. 

Why is this important?

Sign to support us in our call for: 

  • Secondary sewage treatment and UV disinfection on all inhabited islands; 
  • Effective regulation and accurate monitoring; 
  • Preservation of our highly protected marine environment; 
  • Well-maintained water infrastructure and equipment.

In 2026 there are no excuses for sewage pollution.

The Isles of Scilly rest 28 miles off the coast of Cornwall in a gorgeous tapestry of blue-green water. This spectacular marine environment is teeming with life and is home to Grey Seals, Crawfish and Pink Sea Fans, all of which are protected in an archipelago-wide Special Area of Conservation along with reefs and intertidal sandbanks. Other residents and regular or rare visitors are ‘priority species’ and include: 

  • Sea Fan Anemones
  • Sunset Cup Corals
  • Porbeagle Sharks
  • Blue Sharks
  • Basking Sharks 
  • Humpback Whales
  • Fin Whales
  • Minke Whales
  • Cuvier’s Beaked Whales
  • Orca
  • Risso’s Dolphins 
  • Common Dolphins 
  • Bottlenose Dolphins 
  • Harbour Porpoise

And too many more to mention! These species and their habitats - along with magnificent seabirds, wildlife, and flora and fauna on land - are why Scilly is one of the most protected environments in the UK. 

Despite this, South West Water are proposing to construct a fine-screening plant and long sea outfall to ‘improve’ St Mary’s’ already failing sewage system. If successful, this 470m pipe would routinely discharge screened but untreated sewage into highly protected, designated habitats within a fragile ecosystem. St Mary’s has a population equivalent of over 2,000, making it unlawful to routinely discharge untreated sewage here. SWW have stated the necessity for secondary treatment to protect our Special Area of Conservation in their own publications, and the Environment Agency acknowledge it too. Despite this, South West Water are progressing their plans at pace, and the Environment Agency said they will consider a ‘robust’ argument for screening only.

In 2026 there are no excuses for sewage pollution. We know better, and have the technology to be innovative and sustainable whilst we do better. Other UK islands like South Uist and Tobermory have secondary treatment for similar population equivalents, and it would never be acceptable on the UK mainland. People are aware of the sewage crisis and are no longer prepared to let sewage pollution harm our environment and our families.

The Isles of Scilly is one of the UK's most protected marine environments. A place with this level of environmental importance should become a showcase for the highest standards of wastewater treatment—not an exception where lower standards are accepted.

Sign, share, and shout it out loud!
Isles of Scilly, United Kingdom

Maps © Stamen; Data © OSM and contributors, ODbL

Category

Links

Updates

2026-07-15 21:04:20 +0100

Good evening all,

What incredible support you have shown the Isles of Scilly in such a short time. Thank you so much for signing our petition: “Give Scilly the Highest Standard of Sewage Treatment”.

So much has happened already thanks to this wonderful community, so please keep signing, sharing and raising awareness.

We’ve updated our website to ensure we're keeping you up to date with the newest developments; They're coming thick and fast now!

https://www.environmentactionscilly.co.uk

We are now at 650 signatures - can we get to 1000 before morning? Keep checking back to stay in the loop.

With gratitude,
Environment Action Scilly

2026-07-15 14:04:09 +0100

500 signatures reached

2026-07-14 21:44:43 +0100

100 signatures reached

2026-07-14 21:17:58 +0100

50 signatures reached

2026-07-14 21:04:31 +0100

25 signatures reached

2026-07-14 20:48:40 +0100

10 signatures reached