A business park which will provide more than 1,000 jobs has been given the go-ahead.
Brighton and Hove planners voted 7-3 in favour of proposals by the Cuckfield Group after an 80-minute debate.
There was strong opposition from many neighbours, despite several changes to the plans.
More than 50 people held a demonstration outside Hove Town Hall and later packed the public gallery, holding placards.
Three new office buildings will be built on the site of the Alliance and Leicester building at Hove Park.
There will also be 65 flats, 21 of them low cost, in a further three blocks. More than 750 parking spaces will be provided.
Heidi Coplin, of DMH Planning, represented many of the objectors.
She said there would be at least 1,000 workers at the site compared with 800 at the old Alliance building and there would be more if there was 24-hour working.
This would cause traffic and parking problems.
Nevill ward councillor Peter Lewis said: "We are glad to see the old building pulled down.
"But most people do not support the new buildings which will be put in their place."
He said existing roads were near capacity and most people working at the site would be arriving by car rather than by public transport.
Tory councillor Peter Willows said amid cheers: "I am disappointed and disgusted by the design of the buildings."
But planning head Maggie Brian said the new buildings were unashamedly modern, as the Alliance building had been in the Sixties.
Cuckfield Group director Ronald Persaud said the £65 million scheme would be called City Park.
He said: "New homes in City Park will be of the highest standard, some at the upper end of the market with values in excess of £200,000, while state-of-the-art office buildings will provide first class facilities and create major new employment opportunities."
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