Secret documents were withheld from councillors as they took the decision to approve 600 new homes by the Cardington Sheds.
The Campaign For Rural England Bedfordshire claims the developer’s viability report, and an independent report into the project, were kept from members of the planning committee as they contained ‘commercially sensitive’ information.
The plans were approved on Monday despite strong opposition, including appeals from the owner of Shed 2, the Met Office, and English Heritage.
The application was made by site owners Fosbern Manufacturing Ltd. It said the development is essential to fund restorations to Shed 1.
CPRE Bedfordshire vice chairman Gerry Sansom said: “How the committee was able to decide on the merits of the applications is beyond us. The Viability Assessment is the most important part of the application because it goes through in some detail the reasons why the applicant needs this enabling development.
“We are considering what further action we should take to ensure an open and democratic process in the planning system is followed by Bedford Borough Council.”
A council spokesman said a viability assessment looks at the financial picture when considering factors such as location, type of site, size of scheme and scale of contributions to infrastructure but added: “it includes information regarding building costs pertinent to a specific developer and is therefore commercially confidential.
“The council’s appointed independent assessor scrutinised the viability assessment and committee were satisfied that it could be taken as a basis for making an informed decision on the developer’s claims.”