Planning officials penned an angry letter to their boss complaining they were made to feel pressured into backing the £270 million seafront King Alfred development decision, it has emerged.

Brighton and Hove City Council has admitted staff sent the memo to city planner Martin Randall.

But the council has refused to release the correspondence under the Freedom of Information Act because it claims the letter could affect public confidence in the planning process and undermine the decision.

The Regency Society, which has been fighting for the information to be put into the public domain, has appealed against the decision.

The note was dispatched on March 2, 2007 just weeks before councillors voted to approve the development, which Mr Randall had recommended for approval.

The revelation confirms rumours of disquiet among council staff in the run-up to the planning decision.

Three senior officers - the development control manager, area manager and the King Alfred case officer - have since left the department.

It is not known whether the controversial planning decision played a part in their decision to leave, or whether they signed the memo.

The council has argued it is not in the public interest to disclose the contents of the letter because if the information was not viewed in context it would affect public confidence in the planning process and undermine the decision.

The council also believes that releasing the information would not help the public better understand how the decision to grant planning permission was reached.

The council wrote: "We are of the opinion that the public interest in withholding the information would outweigh the public interest in disclosure, as the concerns raised in the memorandum have been responded to and did not necessitate further action or exchanges.

"If the information was disclosed, it could mislead the public and undermine confidence in the planning process."

Michael Ray, the chairman of the Regency Society and a former town planner, said the letter should be released.

He said: "These documents would expose the malaise that prevailed in the city council's environmental services department at the time that the decision to grant consent was made.

"The public is entitled to know what went on.

"I believe that the responsible development control staff were unhappy with the scheme, as submitted, and could not forward a favourable recommendation, preferring instead to negotiate for changes."

A council spokesman said he could not discuss the information request as the appeal was being dealt with by the Information Commissioner.

He added: "As no judicial review is now forthcoming, the planning permission is legally watertight.

"It cannot and will not be revoked due to any document disclosures.

"The public interest would be best served by moving on and ensuring the development really delivers the public benefits promised by the developers."