Amid controversy around EDF's bid to create salt marshes to offset the planned death toll of millons of fish in the Severn from the construction of Hinkley Point C, the boss of Stroud District Council has written an open letter to the French energy giant - and blasted the firm for ignoring her council's authority.

Kathy O'Leary, SDC Chief Executive, wrote to EDF over its ongoing engagement with people in the district for a potential scheme to create new salt marshes at Arlingham.

With permission already signed to build Hinkley Point C, the new nuclear power plant on the coastline in Somerset, EDF is considering an application to central government to remove an existing Development Consent Order for an Acoustic Fish Deterrent (AFD).

The design detail pertains to a pipe which brings water from the Bristol Channel into the plant to cool the nuclear process, the purpose of the AFD being to minimise any aquatic kife pulled into the pipe and killed. EDF wants to drop this design detail because, it claims, AFDs are dangerous to maintain.

Instead of installing the feature, the firm is now looking into the possibility of offsetting, rather than preventing, fish death by simply creating areas of ecological compensation upstream in the Severn Estuary and Bristol Channel - including a potential new salt marsh at Arlingham, within Stroud district.

In all, EDF is looking at four sites amounting to some 840 acres, where these mitigating salt marshes would be created: outside one in Somerset and another at Littleton-Upon-Severn, in South Gloucestershire, the remaining two are near Westbury-on-Severn and, on the other side of the estuary, at Arlingham.

To smooth the way for the plan - or attempt to - representatives from EDF have hosted public meetings to discuss the idea, but a packed meeting in Arlingham in October, when EDF bosses sought to explain their vision for salt marshes there, saw a hostile reception which garnered national news headlines.

Residents said EDF was "greenwashing" by attempting to offset the damage to aquatic life from the AFD removal, while concerns for impact on the Arlingham peninsula included potential destruction to local wildlife and habitats, including hedgehogs and many endangered species.

Now, in public letter to Andrew Cockroft, EDF's Head of Stakeholder Relations and Social Impact, Ms O'Leary said she found it "very disappointing that EDF has not directly engaged in any meaningful way with the District Council on such a significant issue in advance of approaching communities and landowners."

She added: "In addition, the District Council has not seen any primary technical information about the saltmarsh proposal nor been briefed on the process by which EDF are seeking to take forward their proposals, which means we cannot engage meaningfully."

She has asked the company for reassurance that it will share their evidence and data with the District Council, so it can meet its commitment to serve and support the communities affected by the potential scheme.

If the company, the letter states, goes on to submit a planning application for the salt marsh, the District Council will very likely be part of the statutory decision-making process.

 As such, she said that the letter is not a comment on the scheme itself, but a request for better conversations and community engagement.

Ms Leary concluded: "I would however reiterate the need for improved, early and meaningful engagement with the District Council, together with a greater sharing of technical information, so that the District Council can meet its commitment to serve and support the communities affected by the potential scheme."

In a separate report to the Guardian newspaper, Hampshire-based Fish Guidance Systems, which had been in line to supply the AFD system to EDF, said the move could particularly impact elver populations hit with migrating eels "likely to be sucked into the Hinkley intakes".