Ben Roberts-Smith used pre-paid mobile phones to communicate with solider colleagues after he was accused of war crimes because he was worried about phone hacking, a court has heard.

On his fourth day giving evidence to a high-stakes defamation trial in Sydney, the war veteran blamed two members of Special Air Services Regiment (SAS) for “poisoning the well” by speaking to the media about missions in Afghanistan.

The 42-year-old is suing The Age, The Sydney Morning Herald and The Canberra Times newspapers over a series of 2018 stories, which reported serious allegations against Mr Roberts-Smith related to his Afghanistan deployments, including unlawful killings.

Mr Roberts-Smith told the Federal Court that after reading the first article in June 2018, he spoke to four current or ex-SAS officers who were on the missions mentioned.

After initially using his own mobile phone, Mr Roberts-Smith asked a friend of his ex-wife to buy pre-paid mobiles for further communication.

“My view was that I just needed to talk on something that wasn’t compromised by the media and used in another article,” he told the court.

Mr Roberts-Smith said the News of the World phone-hacking scandal was “playing heavily on my mind”.

He said he spoke with the soldiers about their recollection of the missions and who was responsible for the allegations.

“Everyone had a view on which individuals were trying to poison the well with the media,” Mr Roberts-Smith said.

He said two soldiers, referred to by the pseudonyms Person 6 and Person 7, were thought to be “the key drivers of the negative campaign”.

Mr Roberts-Smith denied he used the pre-paid mobile phones to avoid the attention of the Inspector General of the Australian Defence Force.

He also denied burying a number of USB drives that contained sensitive photographs and information from Afghanistan in his Sunshine Coast backyard.

Mr Roberts-Smith said the drives were sent to him anonymously in the mail and included footage from missions and photographs from parties at the unofficial SAS bar, the Fat Lady’s Arms.

The former soldier recalled attempting to obtain the home addresses of six SAS officers from a private investigator, John McLeod, as he was attempting to work out who was speaking to the media.

He denied ever sending threats in the mail and said while he was never given the addresses, he intended to pass them on to a WA-based private investigations firm so it could discover who was speaking to journalists.

The Victoria Cross recipient appeared to become emotional in the witness box on several occasions when he was asked by his barrister, Bruce McClintock SC, about the impact of the stories on his life and his family.

He told the court it was “traumatising” to get a call from his ex-wife’s parents, shortly after the articles were published, expressing concern about him and his children.

“You fight for your country, you come home,” he began, loudly exhaling and pausing.

“And somebody attacks you from the shadows, like cowards, and your own family has to think that about you.”

Mr Roberts-Smith detailed the impact on his children and said every day he worries about what people may say to them about him.

“It was, and it is, something that just crushes me,” he said.

“It crushes my soul. Because I gave so much to that job. And it’s all lies.”

Mr Roberts-Smith alleges he was defamed by imputations including that he “broke the moral and legal rules of military engagement”, “disgraced his country”, bullied SAS colleagues, and committed an act of domestic violence against a woman in a Canberra hotel room.

Nine Entertainment Co, the publisher of two of the papers, is using a defence of truth.

–ABC