But one of the men at the centre of the initial negotiations says the deal nearly fell over, because of the caveats placed on the block.

Former Sustainable Land Strategy director Greg Ellis believes the government rushed to advertise the Tradies car park in Dickson in 2012 to ensure the CFMEU-linked club had a chance to buy it in case the government changed in 2012 - a claim rejected outright by the government.

However negotiations were hamstrung from the get-go by the constraints placed on the block.

The buyer would not be able to develop the site for four years - a caveat designed to ensure the new Coles development, with its car parking, was completed first to avoid parking chaos - and the bureaucracy had not had time to do the usual due diligence on the block, according to Mr Ellis.

Mr Ellis says that meant the government was never going to get the best price for the land. But he says while such considerations limited the sale price they did not impact on the way he did his job, within the law and to drive a hard bargain.

The site was advertised just ahead of the 2012 election and Mr Ellis spent 2013 negotiating a deal.

The Tradies bid $600,000 higher than Woolworths, but not as high as the government’s reserve, of $3.18 million, and offered just 84 public car parks instead of the 154 the government wanted.

Mr Ellis said talks were fitful and almost broke down when the parties could not find common ground.

In April 2013, with negotiations stalled, then-head of the Land Development Agency David Dawes brought in Colliers to look again at the valuation in an effort to bring the two sides closer.

While the government’s initial valuation, from MMJ, said the land was worth $3.18 million, Colliers revised it down to $2.75 million, taking account of the roadworks the Tradies would have to do.

Mr Ellis said he continued to push the union to offer more, eventually getting agreement at $3.18 million in return for some of the 154 public car parks being provided under the Tradies existing building instead of the new building, saving the Tradies from having to build extra basement levels in the new building, and in return for a land swap. (While Mr Ellis said the car park deal was agreed, the question of how many carparks will be provided appears to remain in contention. )

The government would buy the Tradies’ land on Section 72, near the Dickson playing fields, for $3.55 million and the CFMEU would continue to operate there for about 40 months rent-free.

That deal was made in December 2013.

Mr Ellis has admitted his minute to Mr Dawes outlining the deal contained an error about by implying that the $3.55 million to be paid for section 72 included 40 months rent free for the union, whereas the figure incorporated no free tenancy. Mr Ellis said the mistake overstated the value to the government by about $300,000 and he accepts the error.

He said if he had still been in the job in 2014 he "wouldn’t have any part" of the extra changes, which "would have been a betrayal of the great deal that I’d got”.