The future of Brighton and Hove's most controversial seafront development is secure after councillors gave the scheme their backing in a crucial vote last night.

Architects behind the plans to transform the King Alfred site in Kingsway, Hove, were celebrating last night after the vote, which paves the way for the final planning decison on the long-awaited project. Business leaders were also breathing a sigh of relief.

The city council's influential policy and resources committee voted in favour of the plans after a night of deliberation and deviation from the original proposal.

Councillors met to vote on the £290 million development, which would feature a sports centre and housing including two towers designed by renowned international architect Frank Gehry.

The meeting at Hove Town Hall began with an amendment proposed by Conservative councillor Brian Oxley.

He called for the entire scheme to be rejected and for interested parties to offer alternative proposals and investigate the possibility of moving the housing to another site.

Council leader Simon Burgess called for the amendment to be considered behind closed doors.

After hours of deliberation in which the financial implications of dropping the scheme were discussed, the amendment was rejected by council officers on legal and financial grounds.

Keith Taylor, convener of Brighton and Hove Green Party, put forward a second amendment which read: "The council is committed to work with the developer, for them to provide a meaningful proportion of the housing provision of the scheme in another location, in order to enable it while reducing the overall impact."

This was approved with nine votes for the proposal and six against.

Speaking after the vote, Coun Taylor said the Greens had always objected to the density of the project and the amended scheme would have less impact on Hove and provide better quality public spaces.

"As it stood the proposal would not have made it through planning.

We had two choices we could kick this scheme out or do what we have done - take it and think about it imaginatively."

He did not suggest any alternative sites and said this would be a matter for officers to look into.

It also remained unclear how many of the homes would be taken away from the King Alfred site.

Coun Taylor said he had met developer Karis earlier in the day to discuss possible amendments and had had "positive responses".

Coun Burgess, said: "For much of the evening I thought the scheme was lost but I'm grateful to both the Liberal Democrat and the Green party for finding a way forward.

"I'm excited for the city. I couldn't imagine trying to explain to people from around the world that we had turned down this Gehry design when it could offer us so much.

"This is also good news for the other big projects in the city - the Brighton Centre and Preston Barracks, for example.

"We've proved that having no overall control (on the council) is incredibly challenging but decisions are achievable if members of all parties are willing to show a pragmatic approach."

Brian Oxley, leader of the Conservatives, said his party would now consider asking the Government to call if the committee's decision because the Greens' amendment was not binding.

He said: "The deal that the Greens have struck with Labour is completely meaningless.

"It will make no difference at all to the number of units on the site and a development which is completely out of character with that part of Hove is being approved."

Fellow Conservative Garry Peltzer Dunn compared the density of homes proposed for the site to the rest of Brighton and Hove.

He said that if that density was repeated across the city it would have a population of one and a half million people.

"From the Conservatives' point of view we maintained our objection to the gross overdevelopment of the site. The Greens said they would support us and then did a U-turn."

Coun Oxley said: "My amendment would have opened up a discussion about the density of the site and that's what is at the heart of the concerns of local people.

"I simply don't believe what the business community is saying - that losing the King Alfred would affect our financial future. I haven't seen any hard evidence that that's the case.

"It's been a rocky year for developers and councillors alike and the £290 million project has looked doomed to failure many times. Some would say it still does.

In June, The Argus reported how architect Frank Gehry was told to redraw his seafront scheme.

The council emphasised that the controversial plan would not go ahead in its original form.

Many said it was simply too big but when the plans returned they still contained 751 homes, only three fewer than proposed in the original design.

And councillors have been surprised to learn that of the 276 affordable homes Karis have planned for the site, seven per cent have been earmarked for alternative funding.

Coun Oxley said: "That means £2.7 million is now going to be used as a housing subsidy to make the scheme work. It's obviously teetering on a knife edge.

Sue John, deputy leader, said: "This is an iconic and coherent scheme by a world-class architect.

It relates well to the surrounding area and will provide first-rate sports facilities for everyone in this city in a high-quality, vibrant environment."

Last night's decision will be a relief to business leaders who warned in February that a planned £300 million scheme to redevelop the Brighton Centre could have failed if the King Alfred complex was rejected.

Council leaders revealed they were in talks with major firms to pay for the largest city centre development in modern times.

Investors were being wooed to finance a £100 million state-of-the art conference venue to replace the ageing Brighton Centre.

In return they would be allowed to build lucrative new homes, shops, a four-star hotel, cinemas and other leisure facilities on part of the site currently occupied by the centre and the Kingswest Building.

Tony Mernagh, executive director of the Brighton and Hove Economic Partnership, said investors would have been scared off if councillors had rejected Gehry's King Alfred development.

He said rejecting the development would have been like putting up a sign saying Brighton was closed for business.

Last night he welcomed the council's decision and said he would be interested to see where alternative sites would be found for the housing.

"All in all it's good news for other developments which comply with our very high standards of what we expect in the city."

Josh Arghiros, managing director of developer Karis, said: "From the outset we have been committed to providing an outstanding scheme for this site.

"It is full steam ahead now, and we look forward to developing this world-class scheme for Brighton and Hove."

Prior to the meeting it was believed the Greens and Conservatives would vote together to block the proposal. The two parties held the balance of power, with eight votes against Labour and the Liberal Democrats' seven.

Green Councillor Bill Randall, who had sat on earlier committee meetings, was substitued at the last minute by Coun Taylor. Coun Randall had consistently voted in favour of the proposal. His vote was taken by Coun Georgia Wrighton, who was expected to vote against the proposal but voted in favour of the Greens' amendedment.

Coun Randall, who did not attend the meeting, said he was the only Green councillor to support the scheme and therefore agreed to stand down.

"I warned them that I would vote for the scheme if I went to the meeting. As a result my colleagues took the decision to substitute me.

"I am very pleased that the scheme has been passed I have supported it all the way through."

Liz McSheehy, the South East England Development Agency's area director for Sussex, said: "The design of the structure will be of international importance and will be a major contribution to the urban renaissance of the community."

Members of Brighton and Hove Economic Partnership, who urged councillors to back the scheme on Wednesday, were delighted by last night's decision.

Simon Beales, who runs Brighton fashion label and shop Simultane, said: "This is great news. I understand there are local reservations but from a national and international point of view this is fantastic.

"I think this decision is making a statement. Firstly that we are committed to doing something with a site that is really a bit of an eyesore and isn't useful for the community and secondly that we want something fantastic like this for Brighton."

Dr Clifford Conway, president of Brighton and Hove Chamber of Commerce, said: "I am very pleased. It is a fantastic outcome for the community to have such a prestigious architect build here.

"Economically for Hove the development is fantastic news. "We are increasingly getting competition from Portsmouth, Southampton, Bournemouth and Eastbourne. If we stay with our present retail and building range we are going to lose the race."