A chance discovery ends the trial of Bruce Lehrmann for the alleged rape of Brittany Higgins

The first sign something was amiss in the trial of Bruce Lehrmann came just before 8.30am on Thursday.

A note, sent by staff working for the ACT supreme court chief justice, Lucy McCallum, landed in the inboxes of observers, advising the court would be convening at an unusually early time.

The email set tongues wagging among the press pack that has camped outside the courtroom for nearly a month. Was a juror sick? Were they deadlocked? Did the jury have a question? Had press coverage from the night before caused a problem?

Inside court, there were more signs of the unusual.

Brittany Higgins and her partner, David Sharaz, were also in the public gallery for the first time during the trial, accompanied by the victims of crime commissioner, Heidi Yates.

The mystery was soon solved.

McCallum arrived and quickly told the court that a juror was being investigated for misconduct. The juror was thought to have brought in outside research material into the court, something jurors are told repeatedly not to do.

Everyone, including Higgins and her supporters, were asked to leave the court while McCallum questioned the juror.

The outcome seemed inevitable. McCallum brought the 12 members of the jury in, and advised them someone had brought a research paper on sexual assaults into the jury room, despite repeated directions not to conduct their own inquiries.

She said the court had no choice but to abort the trial.

The misconduct had been discovered by chance.

Each day, before they went home, they were given an obligatory warning against conducting outside research.

McCallum estimated she told the jury at least 17 times not to conduct their own outside research.

The juror responsible cannot be punished in the ACT, whether by fine or other penalty. In NSW, such conduct could amount to a criminal offence.

The decision means the Lehrmann trial ended without an outcome, after almost three weeks of evidence from 29 witnesses, including two former cabinet ministers, and one week of deliberations.

The case had reached this extraordinary crescendo at breakneck speed. It was a marked change of pace from the week prior, filled by days and days of deliberations, some of which passed without so much as a peep from the jurors.

Whybrow emerged from the court building to a media throng. He declined to comment, saying only that the outcome was disappointing.

Then Higgins, fighting back tears with her supporters beside her, issued an emotional statement.

The court declined to comment on any consideration of contempt, saying it did not want to engage in public discourse about remarks made by a participant in legal proceedings.

McCallum had earlier made it clear that she would take a dim view of any further publicity that could prejudice the second trial, which, at this stage, is expected in February 2023.

Lehrmann went into the trial with the presumption of innocence.

That can change if the defence makes an application for a complainant to be brought back in person.

If the trial runs again, it will again draw in powerful political figures.

The court has already heard allegations that Higgins felt pressured by her then minister, Linda Reynolds, into dropping her police complaint about the alleged rape, something Reynolds strenuously denied. It heard allegations that Michaelia Cash, a former attorney general, knew of the alleged rape far earlier than she says, though that has been denied by Cash.