Megan Latham could not have foreseen the devastation that would flow from the arrival of a package of material from the Australian Crime Commission in July 2014.

The package for Ms Latham, the commissioner of the Independent Commission Against Corruption, contained audio and transcripts of phone taps of deputy senior Crown prosecutor Margaret Cunneen, SC, who is heard apparently praying for a miracle.

"Let's hope that St Anthony does a miracle and takes all the alcohol out of the sample," Ms Cunneen was heard telling a tow truck driver whose phone had been bugged.

The ACC was suggesting that Ms Cunneen had attempted to pervert the course of justice by advising Sophia Tilley, the then girlfriend of Ms Cunneen's son Stephen Wyllie, to feign chest pains to avoid being breathalysed at the scene of an accident.

The phone taps showed that on May 31, 2014 Ms Tilley, who was driving Ms Cunneen's car, had been involved in an accident at Willoughby.

Ms Tilley, who was not at fault, later admitted to ICAC that she had been drinking, although when eventually tested at hospital returned a negative blood test for alcohol.

P-platers cannot consume any alcohol and Ms Cunneen appears worried her car insurance might be voided.

On the tapes Ms Cunneen told the tow truck driver she had sent a message to Ms Tilley to "start having chest pains" to avoid a breath test at the scene of the accident. In a second intercepted call, Ms Cunneen said the "chest pains" had "bought her [Tilley] a few more hours".

Ms Cunneen later said she had only been "joking" in the tapes and her partner Greg Wyllie added she was just talking the "same lingo" as the tow truck driver.

Private hearings ensued and in October 2014 Ms Cunneen stood down as a prosecutor after the corruption watchdog announced that an independent commissioner from Queensland would preside over a public inquiry into the matter.

The well-known prosecutor fought back.

"They're out of control, these people," she said of ICAC. "They're a rogue agency. This whole thing, this has to be completely destroyed. It should be part of the police."

But it was concern over Ms Cunneen's friendship with a number of high-ranking police officers, through her role as a prosecutor, that had been the reason the ACC bypassed the police and referred the matter to the ICAC in the first place.

Ms Cunneen successfully challenged the ICAC's jurisdiction to investigate her. The High Court narrowed the interpretation of "corrupt conduct" under the ICAC Act.

The NSW Solicitor-General subsequently advised that she should not face charges over material referred by the ICAC.

Ms Cunneen's victory in the High Court left ICAC seriously weakened in the public eye.

Ms Cunneen alleged that Ms Latham, who had been her boss at the DPP some 25 years earlier, had been fuelled by an unspecified personal vendetta.

It was a claim later denied by Ms Latham, who had subsequently been appointed as a judge of the District Court and later elevated to the Supreme Court.

In her high-profile battle against ICAC, Ms Cunneen, a political conservative who is close to MP Christian Democrat Fred Nile, became the beacon of light for many of those whom ICAC had branded corrupt.

Highly vocal were members of the Liberal Party who had been caught up in a major donation scandal.

Also supporting Ms Cunneen were members of the family of corrupt former minister Eddie Obeid as well as businessmen who were found corrupt through their mining deals with the Obeids.

News Corp and radio figures backed Ms Cunneen in what became a relentless campaign against both Ms Latham and ICAC.

At one point 2GB's Alan Jones suggested that it was Megan Latham herself who should be "in the dock".

Ms Latham's demise was effected when Premier Mike Baird pushed through legislation that meant Ms Latham had to re-apply for her job on a revamped three-person panel.

"How can this be proper?" posed inaugural ICAC commissioner Ian Temby in a letter published in Fairfax Media recently.

Suggesting it was "payback," Mr Temby pointed out that "Megan Latham, SC, was appointed for a fixed term to a date in 2019. Under the ICAC Act she enjoyed the same security of tenure as judges do: subject to dismissal only by Parliament on the ground of proven misbehaviour. That process has been entirely avoided."

As for Ms Cunneen, she told a Christmas lunch on Wednesday that she was pleased "that vindictive woman" had resigned.