The cost of building the i360 on Brighton seafront has more than doubled, with the final bill now estimated to be more than £46 million.
The Latest website reported that the sum was included in a heap of commercially sensitive information presented to Brighton and Hove councillors before they make a decision whether to support the attraction next week.
When plans for the 175-metre tower were given planning consent in 2006 the architects and developer Marks Barfield said that it would cost between £15 million and £20 million to build.
But Latest said that the total final cost would be £46.23 million.
Most of this would come from a £36 million government loan drawn down by Brighton and Hove City Council and handed straight over to the developer.
This would be repaid with interest over a period of more than 25 years.
Councillors will vote on whether to support this proposal at a crunch meeting of the council’s Policy and Resources Committee on Thursday (6 March).
A further £3 million will come from Coast to Capital, the area’s local enterprise partnership, with the rest coming from private funding.
Green and Conservative councillors are expected to support the loan plan but Labour is firmly against.
As revealed by Latest earlier this week, the Tories supported the plan only after a discussion among its councillors on Monday night (24 February).
Of the 18 Conservative councillors, five were against. The Latest website said those opposing the scheme were Mary Mears, Lynda Hyde, David Smith, Geoff Wells and Dawn Barnett.
Councillor Smith said: “I’m not against the i360 but totally against the city council being involved in the financing.”
Councillor Mears said: “Though I support the concept of the i360, they have failed to secure private finance.”
Councillor Wells said: “With big business people uninterested in ploughing money into the i360 in my opinion this could well go pear-shaped leaving local taxpayers picking up a very big bill.”
Councillor Barnett, who represents Hangleton and Knoll, said: “I’ve got a four-year-old great grandson and he’ll be nearly 30 before it’s paid back.
“I think it’s too much money and too much of a risk.
“That money could go towards building a new leisure centre.”
Details on the loan and how it will be repaid are expected to be set out tomorrow (Friday 28 February).
Latest reports that a deal would give the council 1 per cent of all ticket sales for the attraction, which developers believe will draw in up to 800,000 people a year.
The council is also reported to be in line to receive £1 million in fees as well as a profit on the loan.
The council can borrow at a lower rate from the Public Works Loan Board than the commercial rate that it would charge the i360 developer.
It is understood that the difference could be as much as 3 per cent.
The council could receive a further six-figure sum as new government rules mean that it will keep part of the extra business rates generated.
Council leader Jason Kitcat said: “The i360 developers have shown they can deliver successful tourist attractions elsewhere and we believe they can do the same here.
“Not only will Brighton and Hove get a landmark that will put us on the international map, and bring additional visitors to our city – but it will regenerate an area where businesses are struggling.
“That’s why the i360 has strong support from local residents and businesses.
“To help bring this positive project move forward, we are working hard to get the best deal possible for the city and will be able to share more information about the proposals at the end of the week.”