Valuable international business could leak away without a second runway at Gatwick, spelling economic doom across the South-East, warns a new report.

The South-East England Development Agency (Seeda) said the decision to rule out further development at Gatwick until 2009 meant the airport was not fulfilling its potential and the economic impact of both having and not having a second runway needed to be assessed.

The Government has had to introduce further airport consultation options after losing a court battle last summer to miss Gatwick off the list of airports earmarked for expansion.

In its report Seeda said the airport's prosperity was a major influence on the economies of towns within a 30-minute drive and, along with the money generated in Brighton and Hove, was critical to economic growth across the South-East.

The report called for the skills, capability and productivity of the existing and potential workforce at Gatwick to be developed.

It said there needed to be an adequate supply of affordable housing in Crawley and Brighton and Hove to support workers who had been priced out of the market.

Newhaven port should expand, with better links to Gatwick, improvements were needed to the A21, A259 and A27 and an international centre of excellence in management and technology education should be set up.

In West Sussex, the Regional Economic Strategy focused on an "urgent need" to revive the coastal towns of Shoreham, Littlehampton and Bognor, as well as removing bottlenecks on the A23 and A24 at Arundel, Worthing and Chichester.

Seeda's strategy sets the vision, priorities and key actions needed during the next ten years and is backed by the South-East England Regional Assembly and the Government.

It said the Brighton Centre should be knocked down, a tram system developed and the provision of affordable housing in the Brighton and Hove increased.

One of Seeda's highest priorities, along with an in-depth look at Gatwick, was to see a building of world class design replace the much criticised Brighton Centre within ten years.

The development would provide world class conference facilities and be capable of supporting the cultural and leisure regeneration of the city.

Hove MP Ivor Caplin called the Brighton Centre "a hallmark of Sixties and Seventies architecture which frankly the seafront could do without."

He said: "What we must do is keep Brighton as the best conference venue, not just in the South-East but in the UK, because it accounts for 10,000 jobs."

The city's transport network is described as overburdened and a tram system is highlighted as a possibility for the future.

It says the city is characterised by pockets of deprivation, highlighting East Sussex as one of the poorest sub-regions in the South-East and suffering some of the worst deprivation in the UK.

One of the highest priorities in East Sussex was to reinstate the rail line between Lewes and Uckfield, a move that would improve access to Hastings and Bexhill and enable their economies to grow. Rail links should also be improved along the coast from Brighton to Hastings.