The controversial King Alfred redevelopment faces another challenge after one of the city's most respected conservation groups launched a legal bid to block it.

Lawyers working on behalf of The Regency Society have contacted Brighton and Hove City Council in the first stage of a judicial review which could delay or stop the £290 million Hove project.

The news has emerged as The Argus can reveal internal council emails in which consultants warned that granting planning approval for the seafront scheme would allow new developments to overshadow existing homes with impunity.

The High Court challenge will attempt to prove that proper procedures were not followed when planning permission was granted on the casting vote of the chairman of the planning committee on March 23.

The Regency Society declined to comment yesterday but the group is known to hold a series of revealing reports regarding the environmental impact of the development.

The Argus has obtained the same documents under the Freedom of Information Act which show that respected consultants working on behalf of the council warned against giving planning permission.

In an email reporting his initial comments, Dr Paul Littlefair of consultants BRE said: "The daylight impact is really bad.

"In fact, in terms of the number of properties affected and the extent of loss of light to some of them, it's the worst I've ever seen in an Environment Impact Assessment.

"The danger is if you give permission for this, you create a precedent that nullifies any future day lighting constraint you may want to impose on other developments in Brighton.

"It's difficult to imagine any future proposals for any site having a worse impact on more dwelling than this one does."

Concern about the "difficult precedent" was made again in a report to planners at the end of January.

But the warning is one of the only points that does not make it into the final copy of Dr Littlefair's report.

A council spokesman said: "These reports go through various iterations before becoming final.

"The main reason that sentence doesn't appear is because planners strongly disagreed that it would set a precedent and didn't want members misled.

"In any case the final report was very clear on the detrimental lighting effects, it was discussed at length and members were free to turn down the application on that basis if they wanted to."

The Frank Gehry development will replace the eyesore leisure centre on the seafront.

It will feature 751 homes in 11 buildings, including two towers of up to 98 metres and there will be a £49 million sports centre, small shops, a police office, a GP surgery, cafes, restaurants and public spaces.

A spokesman for the council said that the Regency Society still needed to persuade the High Court that there were grounds for a judicial review.

He said: "That cannot be seen as a foregone conclusion, so it may go no further.

"The council has taken the highest level legal advice from QCs since the project's inception and is confident planning permission is legally watertight.

"As such we will be vigorously contesting any legal challenges related to the King Alfred and seeking to protect council taxpayers from having to foot the bill for any legal proceedings."

It is believed that the Regency Society could face bills of up to £30,000 in the fight.