Budget for Olympic Aquatic Centre Triples

Olympic organizers admitted yesterday the budget for the London 2012 aquatic center has more than tripled to £242m. The Guardian understands that a last-minute attempt to hike the price by the contractor Balfour Beatty contributed to the increase in the cost of the troubled project, originally estimated at £75m when London bid for the Games.

The Olympic Delivery Authority also revealed that the cost of the velodrome has increased fourfold since the bid to £80m, double the £40m the Olympics minister, Tessa Jowell, told parliament it would cost just five months ago. A pedestrian land bridge that will adjoin the aquatic center and provide one of the main access points to the Olympic Park will cost £61m.

It conceded yesterday that even allowing for inflation and VAT, which were omitted from the bid book, the price of the swimming pool complex had risen in real terms. It said that the cost was in line with the revised budget published in March last year.

The aquatic center, which will include two 50m swimming pools and a diving pool, has been one of the most contentious projects in the Olympic Park. The London bid made much of their plans for an "iconic" building designed by Zaha Hadid, but within months of being awarded the Games in July 2005 estimates of the final bill had doubled to £150m, and the award-winning architect was ordered back to the drawing board by Jowell to produce a more modest design. The original design was too large for the space allocated on the site, and the bridge would have had to be moved to accommodate it.

The aquatic center will be built close to the main entrance to the park, which is also close to Stratford International station and the Stratford City retail development also under construction. In addition the site is the most contaminated in the park, is crossed by train lines, canals and utility tunnels, and several archaeological sites have been found in the area.

Even after Hadid had scaled down the plans costs continued to rise, and in January this year Olympic sources confirmed to the Guardian that the final bill would be £214m. At that stage the government and the ODA were confident they would resist a demand for an additional increase of more than £25m from Balfour Beatty, but yesterday's admission of the final bill suggests the contractor was successful in raising the price. The ODA insisted yesterday that the overall budget for the venue and infrastructure would not rise, saying the cost of the aquatic centre and bridge was in line with a previously unreleased joint budget for both projects of £303m.

According to the ODA, in January Balfour Beatty agreed a split between the two projects of £214m for the aquatic center and £89m for the bridge. That split now stands at £242m to £61m, which represents a reduction in the bridge budget of almost a third to £61m and an increase in the swimming complex of 12%. A spokesman for the ODA said the changes in the costs of the two projects were not the result of material changes in the buildings but accounting decisions. They ODA also said the overall Olympic Park construction budget of £6.09bn would not be affected.

The ODA explained the doubling of the cost of cycling facilities, saying that the project had been expanded to become a "velopark" that will include a BMX circuit as well as a 6,000 seat velodrome.

The ODA also moved to deny claims by the former chairman Jack Lemley that the final bill for the Games will be £20bn. In an interview Lemley claimed that he was prevented from revealing the full scale of the Olympic costs by politicians including Ken Livingstone. A spokesman for the ODA said: "There has been huge progress since Jack Lemley left the ODA 18 months ago. We are on track to start construction three months early, and the budget has been described by the National Audit Office as soundly based."