Plans to build the largest office complex in Brighton and Hove for 15 years received a huge boost after the developer agreed to complete the final stages of the project.

London-based Mountgrange Capital confirmed yesterday it was ready to start work on phases two and three of the City Park development in The Droveway, Hove.

Builders have been putting the final touches on phase one of the business park, an imposing three-storey building with more than 77,000sqft of office space.

Now Mountgrange has agreed to build two more similar buildings, which will provide an additional 120,000sqft of office space when they open in early 2006.

Manish Chande, chief executive officer at Mountgrange, said City Park would capitalise on a "sea change" in the economic fortunes of Brighton and Hove.

He said: "This investment proves we are confident about the future of the city and the amount it has to offer business in terms of its location and the quality of life it affords.

"From the top floor of phase one you can see the South Downs on one side and the sea on the other. This is exactly the kind of place a responsible employer would want to do business.

"In terms of the availability of labour, Brighton and Hove is in the top ten per cent but as far as the availability of good quality office space goes it ranks near the bottom.

"So it makes perfect sense for us to invest here. There has been a sea change in Brighton and Hove in recent years and we are confident that is set to continue."

There will be 665 car parking spaces once the project is complete - an important factor considering the city's parking problems.

Simon Fanshawe, chairman of the Economic Partnership, said the development would boost the city's growing business credentials.

He said: "City Park will represent another milestone in our desire to help Brighton and Hove become the major business location on the South Coast.

"With possible significant grants available to new employers, City Park will appeal to employers actively looking to take advantage of everything Brighton and Hove has to offer."

The City Park development is the largest and most prestigious office building in Brighton and Hove for 15 years and represents a significant investment in the city's economic infrastructure.

Experts are predicting a shift in the business demographic with more companies looking to relocate outside major conurbations, like London.

Many see Brighton and Hove, with its easy access to London, Gatwick and the Channel Tunnel as ideally placed to become the business capital of the south coast.

Martin Myers, chairman of Mountgrange, said: "Brighton and Hove enjoys all the criteria for attracting large scale employment to the area but employers need a supply of large buildings with large floor space and car parking, given congestion in the city centre.

"Business demographics are changing, with large firms and government departments seeking space outside major conurbations where the combination of environment, good communications and value are becoming paramount.

"The City Park development will provide a highly attractive environment for employers with corresponding appeal to employees.

"We are delighted to be making a contribution to the local economy by deciding to complete the development."

Alan McCarthy, acting chief executive of Brighton and Hove City Council, said: "We are delighted Mountgrange has decided to fully develop the City Park site. Its decision proves once again that Brighton and Hove can provide the best facilities for business."

A sports centre, day nursery and 65 apartments are also being built on the City Park site, which was being developed by Cuckfield Group until Mountgrange took over phase one two years ago.