The controversial King Alfred redevelopment on Brighton seafront has been thrown into doubt after an 11th hour move handed its opponents the power to delay the scheme.

Developer Karis and international financial backer ING have threatened to sue Brighton and Hove City Council for up to £60 million if they frustrate or postpone the process.

Josh Arghiros, the managing director of Karis, and opposition councillors have warned that the decision could lead to businesses and developers shunning the city.

The £290 million Hove seafront project received planning permission in March and the final document was set to be signed at a meeting this week.

But a report, published only hours before the meeting, has now cast a shadow over the Frank Gehry project for a new sports centre and 750 homes.

Developer Karis must pay the council for a range of infrastructure improvements in the city under what is known as a section 106 agreement in the planning permission.

The payments were outlined at the planning meeting in March but building cannot start until the agreement is signed.

But at a meeting of the planning sub-committee yesterday, Conservative councillors pushed through a last-minute proposal to remove the power to sign the agreement from officers and for the financial conditions to be brought back for committee approval on July 18.

The leader of the opposition, Labour councillor Gill Mitchell, and Mr Arghiros have claimed this is an attempt to derail the proposal and frustrate the developer.

Chairman of the planning committee Ted Kemble said the decision was made to ensure the process was open and democratic and that the council had followed proper procedures.

It is feared the Tory-dominated committee could delay the final go-ahead indefinitely, effectively scuppering the plan.

After the meeting, Mr Arghiros told The Argus: "It's a political manoeuvre to stifle the King Alfred project - they gave no good planning reasons for doing this. There is an obligation under the development agreement for the council to act in good faith.

"It took them three months to produce the section 106. We will go at this with such legal vigour the city will be reeling from the repercussions for years."

Concern has been raised that the decision could set back a series of major redevelopments in the city, including plans for a new Brighton Centre by Standard Life and the council.

Mr Arghiros said: "It is a question of this city's credibility.

How do you think Standard Life will feel looking at this? The point that will be made is you can't do business in Brighton."

In an letter from ING to the council's chief executive Alan McCarthy, the firm warns it will use public and private law to pursue the council and councillors.

Officers began working on the section 106 report after Coun Kemble raised the issue at the last planning meeting three weeks ago. But members of the committee were told only yesterday of the Tory plan.

Coun Kemble said the report had not been released earlier because legal advice was received only the night before.

He defended his party's decision: "The original planning application was put through with 85 conditions, the highest number of any planning applications, while at the same time we are not fully aware of what the section 106 conditions are.

"In the interest of openness the answer should come before a public meeting."

Council leader Brian Oxley said he could not answer questions last night as he would need to take legal advice from council officers first.

Ted Kemble, chairman of the planning sub-committee, asked if the decision would put off other developers, said: "I do not think it will frustrate other developments that aim to put major projects before the planning committee.

"Our group has free votes on planning applications."

Was the decision taken for the good of the city or for the Conservatives to fulfil their manifesto pledge? Mr Kemble said: "The decision was not taken for the Conservative manifesto. It is in the interest of openness and democracy that the report comes back to the meeting."

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