the sculpture was constructed in sheffield by thomas heatherwick studio, packman lucas, flint and neill and westbury structures. it was approved at the start of 2003, with the central core arriving in manchester on the 13 june 2004. this was the largest load that could be transferred via road from the factory, and required a police escort. this central core was lifted into place in august 2004, after which the 180 spikes could begin being attached. early estimates had given an optimistic completion date of july 2003, which contributed to the sculpture gaining the nickname "g of the bang".