Developers of what would be the UK’s biggest solar farm planned for the Suffolk/Cambridgeshire border have been asked to provide more detail on the proposals - amid serious concerns over its impact.

At 2,500 acres, the Sunnica energy farm would more than twice the size of the next biggest planned in Kent - and would also require an expansion to Burwell Substation and underground cabling.

In its preliminary environmental information report, Sunnica says it will “provide vital new energy infrastructure required to ensure security of supply to the UK” and “provides an important role in moving the UK away from its reliance on fossil fuels”.

Suffolk County and West Suffolk councils’ cabinets unanimously agreed their responses on Tuesday in which they called for much more work to establish the impacts on the local communities, environment and biodiversity.

Other questions have been posed over the archeological impact, safety of planned lithium ion batteries to store the energy and doubt cast on the transport modelling.

But councillors for the villages around Newmarket, including Worlington and Freckenham, have expressed vehement opposition to the scheme.

Councillor Louis Busutill said: “There is almost universal opposition to the Sunnica proposal.

“The local residents are very upset about the overbearing nature of this proposal and its close proximity to the houses of Worlington and Freckenham.

“Clearly residents are not opposed to solar power per se – in fact we are very proud of the Toggam Solar Farm that is located two miles north of Lakenheath, which is very successful in hiding it out of view of local residents.

“This will not be the case for residents of Worlington and Freckenham who have said that although they are not opposed to solar power they do not want to live inside a power plant.”

Councillor Rachel Hood added: “On behalf of West Suffolk residents I do want to highlight that the size of this proposal is monstrous.

“2,750-plus acres is completely inappropriate and the amount of solar energy that will be provided is a fraction of what would be provided if it was in a more suitable place, i.e. not in the middle of Suffolk that doesn’t get that much sunlight.”

The councils’ responses have called for more information on the impact it will have on climate change emissions, archaeological investigations required, mitigation for wildlife species, flood considerations and visual impact.

The responses said that the “assessment of impacts on the economy is flawed” while the “impacts on highways and transport must be evidenced more clearly”.

Suffolk County Council cabinet member for the environment, Richard Rout, said: “At this stage of the process we have many questions to which the answers are not entirely clear, so it’s appropriate at this stage to take these issues to the developer.”

He added: “The sheer scale of the project means its impact will be significant and very far-reaching.

“It’s our view that the largest solar project in the UK should take an exemplary approach to mitigating its impact on the landscape, so much more work is necessary.”

As a nationally-significant energy project, the government will make the final decision, with the development consent order expected to be submitted to the Planning Inspectorate from spring next year.

That will then undergo a public examination, probably from summer 2021, before a final decision from the secretary of state, also from summer 2021.

If approved, construction will take around two years, with a plan of being operational by Spring 2025.

It would be decommissioned in 2065.

Luke Murray, project director for Sunnica, said: “As part of the consultation, we are actively seeking feedback on the preliminary findings of our environmental impact assessments and our design proposals.

“We are grateful to West Suffolk Council and Suffolk County Council for responding to the consultation.

“We will have regard to their comments alongside every response we receive by the close of the consultation period on December 18 2020.”