Dozens of former SAS soldiers who could be called as witnesses in the Ben Roberts-Smith murder case have been told by the Office of the Special Investigator that their identities are no longer protected and they will have to apply to a judge to remain anonymous.

The letters surprised some veterans of the elite regiment who appeared in a defamation case mounted by Mr Roberts-Smith and were granted pseudonyms to testify for or against the famous ex-corporal.

Two sources with first-hand knowledge of the case said potential witnesses have been told they are no longer covered under a Defence Department regulation known as “protected identity status” that prevents current SAS soldiers, commandos and some other soldiers from being named without their permission.

The rule used to apply to retired and ex-special forces soldiers but was changed ahead of the prosecution of ex-SAS trooper Oliver Schulz on a murder charge, according to a source.

The development will force veterans to seek court orders if they want to testify anonymously, further complicating what has already been dubbed the “murder trial of the decade”.

The Office of the Special Investigator, a Federal agency allocated $300 million to pursue veterans, said it did not comment on “operational matters”. The Defence Department declined to disclose when the identity rule for special forces veterans was changed or why.

Mr Roberts-Smith’s case will return to the NSW Local Court next Tuesday and on September 8 for procedural hearings about the handling and presentation of evidence against Mr Roberts-Smith, who is accused of responsibility for the death of five prisoners in Afghanistan between 2009 and 2012.

More popular than Trump

Despite the serious charges, the Victoria Cross awardee has significant public support. Research published Tuesday found that Mr Roberts-Smith is the second most popular public figure among One Nation voters after party leader and founder Pauline Hanson — and much more liked than US President Donald Trump.

Mr Roberts-Smith is regarded favourably by 69 per cent of One Nation supporters and unfavourably by 17 per cent, according to a poll of 1014 people conducted for Fitzpatrick & Co, a political consulting firm associated with the Labor Party.

The firm’s special counsel, Bruce Hawker, predicted Mr Roberts-Smith’s murder trial, which is likely years away, would split society in a way not seen since Australia’s most famous bushranger was tried and executed for murder in 1880.

“What we believe is when this thing comes to trial we are going to see very significant divisions and a level of campaigning around the issue that we probably haven’t seen in respect of someone who has been accused of such a serious crime since Ned Kelly,” he said.

An April survey by the same pollster found 50 per cent of Australians favoured the veteran compared to 30 per cent who did not, although were evenly split on whether he should have been charged.

Confidential evidence

Mr Roberts-Smith, who is required under his bail to live in Brisbane and can only leave Queensland under strict conditions, does not plan to attend either upcoming hearing in Sydney, according to a source involved in the case.

Almost five months after charging him with war crimes, the Federal Director of Public Prosecutions has not presented any evidence.

At Tuesday‘s hearing prosecution lawyers are expected to ask a judge to approve detailed procedures for providing confidential documents and information to Mr Roberts-Smith and his legal team, led by Perth solicitor Karen Espiner, the founder of Leightons Law.

The court orders governing handling of the information under the National Security Information Act, possibly including the names of potential prosecution witnesses, photographs of dead bodies and contemporaneous military records, could be up to 60 pages long.

Once the court orders have been issued, prosecution lawyers are expected to provide Mr Roberts-Smith’s lawyers with two versions of the evidence, known as a brief. The first handed over will be a “non-sensitive” version of the evidence in which sensitive information is redacted.

An unredacted version of the brief will be provided later to lawyers who have been issued security clearances to read classified information. At the court hearing on September 8, prosecutors are expected to indicate when that version of the brief will be shared with Mr Roberts-Smith, who successfully argued in April that it would be difficult to access confidential military records in prison after prosecutors opposed his bail application.

In June a prosecution barrister, Chelsea Brain, told a judge the brief of evidence “will be substantially complete and ready to serve” by September 1.

138 witnesses

One of the legal complications of the evidence is the identification of SAS witnesses who gave evidence in Mr Roberts-Smith’s unsuccessful defamation lawsuit against newspapers owned by Nine Entertainment Co for accusing him in 2018 of war crimes.

At least 138 witnesses in the lawsuit were covered by pseudonyms, an approach that protected the anonymity of SAS soldiers who provided journalists with information or were accused of executing prisoners themselves.

In criminal cases, witnesses are generally expected to testify under their own names, although exceptions can be made for victims of sexual crimes and domestic violence or when national security is at stake.

The identities of four former soldiers who have agreed to testify against Mr Roberts-Smith in return for immunity from prosecution for murder are covered by separate non-publication orders issued in the NSW Local Court.

While many former SAS soldiers are open about their membership of the regiment, including Liberal MP Andrew Hastie, some are concerned that being connected to allegations of abuses during the war could expose them to a terrorist attack. Preserving his accusers’ anonymity may disadvantage Mr Roberts-Smith, who will need to convince jurors to disregard the prosecution evidence against him.

Separately, Liberal leader Angus Taylor and former prime minister Tony Abbott this week participated in a week-long fundraising bicycle ride through Queensland known as “Pollie Pedal” for Wandering Warriors, a veterans’ charity previously associated with Mr Roberts-Smith.

Last month the charity presented a petition to Parliament asking for the Office of the Special Investigator to be shut down.