Residents have compared the plans to children's game Ker-Plunk

The consortium behind the Manchester project failed to take into account the cost of installing the B of the Bang spiky structure when it submitted its initial bid of £750,000.

Work is due to begin on the 184-feet steel sculpture - which will be the UK's tallest sculpture - next month.

Planning permission for the sculpture was granted two months ago.

The structure was commissioned after an international competition to mark the success of the Manchester Commonwealth Games.

The winning design by Thomas Heatherwick is a tilted structure of 180 tapered steel spikes, connected together at a central point 22 metres above the ground.

'Unique, dramatic'

But some residents have branded the project a waste of money and have likened it to children's game Ker-Plunk.

A spokesman for New East Manchester, the regeneration project which commissioned the sculpture, said: "Initial costs submitted for the installation of B of the Bang were an estimate.

"As many people will have seen, the piece of art is unique and dramatic.

"It was only after the decision to commission the sculpture was taken that the designer and construction company were able to carry out the detailed tests and analysis required to determine the methods and materials required to install it."