Mr McCready had charged that between November 2010 and November last year, Mr Brown accepted for himself and his wife Shan Inglis three complimentary hotel rooms and five free room upgrades from SkyCity and SkyCity Grand Hotels.
The gifts, worth about $4600 by Mr McCready's calculations, led to "favourable consideration" given by Mr Brown towards SkyCity and parent company SkyCity Casinos, his charging documents said.
In his letter, Mr Heron said while complimentary hotel rooms and room upgrades were capable of amounting to a bribe in that they could be viewed as a benefit or valuable consideration, Mr McCready's charging documents alleged that Mr Brown had accepted a bribe "in return for favourable consideration to be given by [him] in his official capacity for future dealings by the Auckland City Council with [the SkyCity Entertainment Group Limited]".
But there was no evidence to link receipt of the hotel rooms or upgrades with any act "done or to be done by Mr Brown in his official capacity so as to satisfy the third element of the offence" - that the bribe was accepted in respect of an act in his official capacity.
There also had to be evidence that Mr Brown knew the complimentary hotel rooms and room upgrades were provided in connection with support for SkyCity but in Mr Heron's assessment, the circumstantial evidence relied upon by Mr McCready to prove corruption fell far short of satisfying that test.
"I have determined that the evidence which the prosecution can adduce in court is insufficient to provide a reasonable prospect of conviction in this case.
"As the evidential test for prosecution is not met, it cannot be said that the proposed prosecution is in the public interest (and I am not required to consider that limb)," Mr Heron said.
Mr McCready told APNZ he wasn't disappointed with Mr Heron's decision and was instead grateful he now had some guidelines to worth with.
"Because I'm not emotionally involved I'm independent and detached I don't get disappointed. We're just representing the public's interests," he said.
"It's all precedent setting, it's legal history in the making and I'm privileged to be part of it."
Mr McCready was yet to read all of Mr Heron's decision. He said he understood his private prosecution was vetoed because it didn't meet the required evidential threshold that Mr Brown knew when he accepted gifts they were intended to influence his vote.