Bruce Lehrmann was "defriended" and kicked out of social and professional messaging groups after rape allegations against him were broadcast, he has told a court.
"I became severely isolated," the 28-year-old man said on Wednesday.
While he had not done so during a criminal trial held last year for a charge of sexual intercourse without consent, Mr Lehrmann took the Federal Court witness stand to give evidence.
"I recall logging back into my social media accounts to shut them down because of the media furor that was erupting, and I observed not only being removed from group chats but people [were] blocking me," Mr Lehrmann said.
"My total number of friends on Facebook had reduced, meaning people had unfriended me."
He is suing Network Ten and journalist Lisa Wilkinson over a February 2021 story on The Project, which revealed Brittany Higgins' claims of being raped at Parliament House two years earlier.
The defamation trial is expected to run until mid-December, with counsel for Ms Wilkinson and Ten relying, in large part, on a truth defence.
They are aiming to prove that allegations Mr Lehrmann raped Ms Higgins when the pair worked together are "substantially true".
On Wednesday afternoon, barrister Steven Whybrow SC asked his client if people began treating him differently after the program in question aired.
"Drastically, yes," Mr Lehrmann responded.
The court heard about several messaging groups the man had been a part of prior to allegations surfacing, including one called "the triumvirate" with two of Mr Lehrmann's closest friends.
"I was booted out of that group in the week after The Project airing," he said.
The television report did not name the former Liberal staffer as the alleged perpetrator but Mr Lehrmann asserts he was identifiable.
As a result of growing online isolation and due to "quite disgusting" social media treatment, the former Liberal staffer said he shut down most of his online footprint.
"It sent me into a deep spiral," he said.
"I've worked out who my real friends are, that's for sure. Which are not many."
Mr Lehrmann reached an out-of-court settlement with News Corp and news.com.au's political editor, Samantha Maiden, in May, over the initial reporting of Ms Higgins' rape allegations.
On Wednesday, the court heard he had also settled legal action against the ABC, whom he was pursuing for damages over the broadcast of Ms Higgins' 2022 address to the National Press Club.
Mr Lehrmann has always denied raping Ms Higgins at Parliament House in 2019, when the pair worked for senator Linda Reynolds.
No findings were made against him.
His criminal trial was aborted last October because of juror misconduct, with the charge levelled at him later discontinued.
- Support is available for those who may be distressed. Phone Lifeline 13 11 14; Canberra Rape Crisis Centre 6247 2525.
