A £325M vision to transform Southampton’s waterfront into a world class “marine basin” with a giant promenade has been unveiled.

Developers yesterday revealed plans for a development that would reshape and dramatically increase the size of the Royal Pier district.

The latest scheme would see the derelict pier demolished – at a cost of £3m – and in its place a new promenade would stretch from Mayflower Park across the water to Town Quay.

But last night those behind the scheme were warned that the people of Southampton must not be left with any more “broken promises” over plans for the waterfront.

Taking inspiration from Sydney and Cape Town, the site would become a circular basin with sweeping views of Southampton Water.

Interactive map of the waterfront development plan

To create much-needed space, Red Funnel’s ferry terminal would be relocated to either the end of Mayflower Park, adjacent to berth 101, or to the Town Quay marina.

The latest ideas were yesterday put forward by Scottish developers Kilmartin, who are one year into an 18-month exclusivity agreement with the council.

However, many specific details were still lacking from a briefing for business bosses and even Southampton City Council leaders admit that construction would not begin for at least two years.

The boss of the PSP Southampton Boat Show said that redevelopment of the waterfront was vital for its future.

Shops, restaurants, hotels and offices make up the bulk of the new proposal, but a major tourist drawcard – such as an arena, heritage attraction or casino – has been made a priority.

Kuti’s Royal Thai Pier restaurant would remain untouched, as would Mayflower Park.

Colin Banyard, the Kilmartin chairman, said that the Royal Pier scheme was the most complex he had worked on.

“We believe that this site has the potential to provide a world class waterfront venue akin to Darling Harbour in Sydney or the Victoria and Albert Docks in Cape Town,” he said.

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“In many of these examples we have this same mix of an active port, busy ferry services and yet the mix provides an exciting and vibrant waterfront that is a main attraction in these cities.”

Central to the new plan is the need to accommodate the boat show, which pumps about £11m into the economy each year.

Mr Banyard said that additional space would be created to allow more exhibitors on both the water and land.

The relocation of the Red Funnel marshalling yard would free up space, while permanent marina facilities – as well the boat show’s own temporary marina – would allow the likes of Sunseeker to show off more of its floating fleet.

Andrew Williams, chief executive of National Boat Shows, said: “The redevelopment will give us the space, location, access and facilities to make us the best show in the world again. If the development does not happen then we will keep going backwards.”

Councillor Royston Smith, Cabinet member for economic development, said that the council was under no obligation to take Kilmartin’s proposal forward.

He said that the site would be marketed to developers in February and he was hopeful of appointing a firm by the end of the year. Planning approval would probably take another 12 months, by which time it is hoped the economic slump will have lifted.

“This is a once in a lifetime opportunity.

If we do not get this one right we will have failed,” Cllr Smith said.

“I would rather see it take ten years rather than it being a second-rate development in this location.”

Previous plans to redevelop Royal Pier were scrapped two years ago because of the £20m cost of land reclamation to increase the size of Mayflower Park.

Mr Banyard said that land reclamation would most likely still be needed, but only at the northern end of the park at a cost of about £12m.

Heavy-bearing piers and bridges would connect the extended park with Town Quay, which Mr Banyard said would also be given a new lease of life. He said: “We strongly believe that any reclamation or pier structure needs to connect to Town Quay to revive its fortunes.”

Another reason the waterfront has laid dormant for so long is ABP’s objection to high-rise apartment blocks being so close to its port operations – a stance port director Doug Morrison reiterated.

“ABP desperately wants to see a world class front here, but we will not allow any residential in this area,” he said.

In 2007 a proposal for at least 1,000 flats rising on the pier and a vast swathe of reclaimed land failed.

Mr Banyard – whose proposal will go out to public consultation in the new year – said that any new homes would be built to the north of the site, close to the De Vere and Holiday Inn hotels.

How will it be paid for?

EXACTLY how the new waterfront and Red Funnel relocation would be paid for remains unclear. Last night the ferry company was unavailable for comment, but it is understood that it would not be expected to pay for its move.

Colin Banyard, chairman of developers Kilmartin, said that the sale and lease of space for offices, shops, hotels and restaurants would generate “significant income”, but that there would need to be other development to cover any shortfall.

As previously reported by the Echo, this could include a large casino or 10,000-seat indoor arena, but where either of these huge buildings would be located remains a mystery.

Mr Banyard also revealed that almost every hotel operator in the UK had expressed an interested in building on the site.

But last night the council was issued with a stark warning over the proposals.

Liberal Democrat city councillor John Slade said: “Any investment in the city is good, but we don’t want to end up with more empty promises.

“All too often we see schemes which are put on the table and then they don’t materialise any further.”