Bruce Lehrmann's barrister says he was "pissed off" when he sent an angry email to the ACT's top prosecutor to complain about claims a senator had tried to "coach" his questioning of Brittany Higgins.
Defence barrister Steven Whybrow SC took the stand on Monday as an inquiry into Mr Lehrmann's case entered its second week.
The independent inquiry is examining the conduct of authorities during the abandoned case of Mr Lehrmann, who has always denied raping Ms Higgins at Parliament House when the pair were Liberal Party staffers.
One of the most dramatic days of Mr Lehrmann's trial, which was aborted because of juror misconduct, involved allegations Senator Linda Reynolds had tried to "coach" Mr Whybrow's cross-examination of Ms Higgins.
ACT Director of Public Prosecutions Shane Drumgold SC put that proposition to Senator Reynolds, who employed Mr Lehrmann and Ms Higgins at the time of the alleged rape, during the politician's evidence.
In doing so, he revealed the senator had texted Mr Whybrow to tell him messages between Ms Higgins and another former staffer may be "revealing".
On Monday, the inquiry heard Mr Whybrow had emailed Mr Drumgold after that was canvassed in court.
"I am ... very concerned that you put is [sic] as a positive assertion that [Senator Reynolds] was trying to coach me or give me cross-examination tips," Mr Whybrow wrote.
"It was not even remotely open in my view to make that bold a suggestion - I am gravely concerned at this late stage about the fairness of this trial by a suggestion which is clearly being reported as some sort of improper conduct between a witness and myself."
Asked on Monday about the email, Mr Whybrow said he had sent it because he had been "pissed off".
Mr Whybrow also took issue with a letter Mr Drumgold wrote to the ACT's chief police officer in November 2022, saying it contained "an appalling mischaracterisation" of Senator Reynolds' conduct.
In the letter, Mr Drumgold repeated the claim about "direct coaching".
The prosecutor also alleged Senator Reynolds had arranged for her partner to attend court and that she had sought transcripts from Mr Whybrow in order to "tailor her evidence".
Mr Whybrow told the inquiry there was nothing improper about defence lawyers having contact with witnesses, who would often provide tips.
In relation to Senator Reynolds' partner attending court, Mr Whybrow said he could not understand why Mr Drumgold had been so worried when members of Ms Higgins' "camp" had been there too.
"I don't hold a candle for Senator Reynolds but [the assertions about her] were unfair and, as far as I was aware, untrue," Mr Whybrow said.
He said he had also been concerned Mr Drumgold had, during closing addresses, put these claims about Senator Reynolds to the jury as positive assertions of some kind of political conspiracy when there was no evidence one existed.
Mr Drumgold last week conceded he had been "mistaken" about suspicions the former Coalition government had pressured police to make the case against Mr Lehrmann "go away".