Who knew what and when? Trial hears new details of timeline after Brittany Higgins’ alleged rape

"Are you familiar with the term 'plausible deniability'?"

The prosecutor's question, posed to Senator Michaelia Cash on the last full day of evidence in the Bruce Lehrmann trial, cut to a critical issue that has hovered around the alleged rape of Brittany Higgins in the early hours of 23 March 2019.

How high up did knowledge of Higgins' alleged rape go before it exploded into public view in February 2021? And who knew what, when?

During the course of the three-week trial, the ACT supreme court has heard new details about the timeline.

Higgins has said she repeatedly told her superiors in the two Coalition offices she worked in from 2019 to 2021: the offices of Cash and the then defence industry minister Linda Reynolds.

The court has also heard Higgins' fellow political staffer and ex-boyfriend Ben Dillaway approached the prime minister's office 11 days after the alleged rape, seeking more support for Higgins.

Higgins says she told Reynolds and Reynolds' chief of staff, Fiona Brown, soon after the alleged rape, including in a meeting on 1 April 2019 held in the same office where the alleged assault took place.

Brown disputes Higgins' timeline while Reynolds flatly denied learning of the alleged rape during the meeting, saying she only knew a security breach had occurred, that Higgins had entered her office after-hours, that she had mentioned getting dressed and appeared to be distressed.

Reynolds said she told her "I'm not a trained counsellor and I'm not the person to be having this conversation with".

"So I suggested to her that I knew we had AFP in the building and that here in the ACT they're community policing, so I suggested to her that she might rather have this conversation with somebody more qualified and that she should talk to the AFP."

Prosecutor Shane Drumgold SC suggested to Reynolds that she was aware that Higgins had made an allegation that Lehrmann had been "on top of her" by that point.

He said: "Would you agree that in the run up to election that having an allegation that one staff member sexually assaulted another staff member would be potentially politically embarrassing?"

Reynolds said: "No, I do not accept that."

Higgins also says she told Cash of the alleged rape multiple times. The prosecution alleges Cash's office first learned of the alleged rape following an inquiry from a Canberra Times journalist in October 2019.

The court heard that the journalist's inquiry, which concerned a security breach in Reynolds' office on the same night as the alleged rape, had prompted a flurry of activity within Reynolds' and Cash's offices. It triggered meetings between Higgins and Cash's chief of staff, Daniel Try, and Cash herself.

"We had multiple conversations and they were all sort of pertaining to this incident itself and how it was handled and why I was so unhappy about it and - yes, we had many conversations," Higgins said in the first week of the trial.

On Monday, Drumgold put it to Cash that she had known about the alleged rape as early as October 2019.

Cash agreed she had spoken with Higgins but knew nothing about an alleged rape.

"[The] first time she mentioned a sexual element was, I think, in the conversation on the 5th of February 2021," she said.

The court heard that Higgins, as she prepared to leave Cash's office, recorded that February 2021 conversation.

Higgins said she did so for her own legal protection, and said she needed evidence that Cash had known about her alleged rape since 2019. Higgins said she then shared the audio with friends.

During the conversation, Higgins said Cash appeared not to know basic details of the allegations.

"It was so strange because the entire call she was pretending like she didn't know and that she thought a security guard assaulted me," Higgins said. "Like, it was ridiculous. It was the weirdest phone call I've ever had in my life."

On Monday, when Drumgold asked Cash whether she knew what the term "plausible deniability" meant, she responded: "I'm not quite sure what you're referring to. You'd need to put it into context."

Drumgold then put it to her that she'd known about the alleged rape since October 2019 but was denying it because it was politically embarrassing.

Cash responded: "Absolutely not. As I said, I just don't understand the line of questioning in relation to political embarrassment. I don't know how it could be politically embarrassing."

Higgins also says she told Try, Cash's chief of staff, about the alleged rape following the journalist's inquiry in 2019.

The court heard Try was alerted to the journalist's inquiry by Reynolds' office, who wanted to send someone over to talk to Higgins about it.

Try said he didn't ask what specifically the journalist's inquiry was about, but said he met with Higgins to alert her. He said he didn't ask Higgins for specifics either.

"Brittany looked quite upset when I told her," Try told the court. "She didn't really say much else at the time."

Try said he learned only that there was a security incident, which he had guessed involved Lehrmann, and that Higgins had been found by security in a "dishevelled" state.

He then established a sit-down meeting between himself, Cash and Higgins, because he thought the minister would be concerned for Higgins' welfare.

Drumgold suggested to him that he had known of the alleged rape, but had wanted to protect his minister from the political fallout.

"I'm suggesting to you that in October 2019, when there was a media inquiry, your dominant concern was potential political fallout?" Drumgold said.

Try responded: "That's not true at all. I was worried about Brittany."

Drumgold pressed on: "I'm suggesting that minister Reynolds gave you all of the detail about the events of the early morning of 23 March 2019 in her office. And your role thereafter was to protect Senator Cash from any political fallout from that moment."

Try responded: "That's not true."

Lehrmann has denied the allegation that he raped Higgins and is fighting one charge of sexual intercourse without consent.

The jury retired to begin its deliberations on Wednesday afternoon. It will continue deliberations on Monday.