A mystery developer given exclusive rights to buy Knowle is proposing to demolish the site’s existing buildings and transform it into a retirement community.

A total of nine bids were submitted for East Devon District Council’s (EDDC) current HQ, and its leaders have now selected their preferred firm to redevelop the 4.7-acre plot.

Campaigners have responded to the news by saying that a retirement community would be a ‘clear breach’ of planning policy.

Updating members on EDDC’s office relocation project, deputy chief executive Richard Cohen said the unnamed developer has been granted a ‘period of exclusivity in which to explore their proposal in further detail’.

He told the scrutiny committee: “The bid that we have preferred is one which involves a mix of retirement community, extra care housing and supported living and a range of other facilities.”

When asked whether any of the bids involved preserving and refurbishing the current buildings, Mr Cohen said: “Nobody was interested in retaining any of the existing structures.”

He added that the council was respecting the developer’s wish to remain anonymous at this stage.

EDDC’s proposed relocation would see it leave Sidmouth and move to a purpose-built new home at Heathpark, Honiton, and utilise and refurbish Exmouth Town Hall’s vacant space.

But the authority first needs to sell its HQ at Knowle in order to finance the project.

A spokesman for campaign group Save Our Sidmouth said a retirement community at Knowle would contravene rules set out in the emerging East Devon Local Plan.

The draft plan acknowledges that many towns in the region have an ‘overtly aged’ population and encourages residential development suitable for younger people and families to address the age balance.

The spokesman added: “The relocation project has reached such a desperate point, as its finances deteriorate, that EDDC is repeatedly prepared to go against its own policies to progress its delivery.”

Any application to build on the Knowle site would need to go through the formal planning process before being considered by the council’s development management committee.