Losses of £520,000 ($803,000/€707,000) for the last financial year were made at the Orbit Tower in the London 2012 Olympic Park, according to accounts published by the London Legacy Development Corporation (LLDC).
This was despite a forecasted growth of almost £1.2 million ($1.85 million/€1.6 million).
The tower, officially known as the ArcelorMittal Orbit, was constructed largely due to funding by the steel giants ArcelorMittal but also cost £3.1 million ($4.7 million/€4.2 million) of public money.
After opening ahead of the Olympics and Paralympics in 2012 as an observation tower, it subsequently closed to be adapted for long term use as a "public outdoor space" before re-opening in April last year.
Designed by Turner Prize-winning artist Anish Kapoor, it is built from about 2,000 tonnes of steel and, at a height of 114.5 metres, is the tallest sculpture in the world.
It allows visitors to see more than 20 miles across London on a clear day, from either the 76m or 80m platforms, it is claimed. while it is also possible to abseil down the tower.
An annual total of 350,000 visitors was initially forecast, but just 124,000 visits were made between April 2014 and March 2015.
More work is now due to take place on developing a giant 178m slide down the tower, which is expected to be completed next year,
Commissioned in 2008 shortly after the election of Conservative Boris Johnson as Mayor of London, the Orbit has now been dismissed as a "vanity project of towering proportions" by Len Duvall, a member of the London Assembly for the opposition Labour Party.
"It looks like we can now add the Orbit to the growing list of failed Boris Johnson pet projects alongside the Thames cable car, estuary airport and fault-riddled Boris bus," he added.
“The Olympics was meant to be a grand celebration of sport, not an excuse to build pointless monuments at vast taxpayer expense."
The LLDC, the body responsible for the redevelopment of the Park, have defended the Orbit, however, and claimed it is still in the process of establishing itself as a tourist hub.
"The ArcelorMittal Orbit was one of the standout successes of the 2012 Games and has seen almost 200,000 visitors since reopening in 2014, which is a tremendous achievement." they said in a statement.
“Hundreds of thrill-seekers have already abseiled from the top of the sculpture and we’re excited at the prospect of welcoming thousands more to experience the exhilaration of riding the world’s longest and tallest tunnel slide, experiencing a new way to engage with the ArcelorMittal Orbit.
“In the coming years the Stadium will be fully open and drive additional visitors to the Park, many of whom will want to visit the ArcelorMittal Orbit.”
April 2015: Iain Edmondson: What have the Olympics ever done for us?
April 2014: Mike Rowbottom: Come on up! Will London 2012's towering legacy grow on us?
April 2014: ArcelorMittal Orbit set to be centrepiece of latest reopening of Queen Elizabeth Olympic Park
January 2012: Exclusive: "No extravaganza" and "no white elephant" at London 2012 claims Rogge
January 2012: Legacy of three more London 2012 venues secured