Lawyer X, who was at the centre of a police informant scandal in Victoria, can be named as Nicola Gobbo after judges denied a last-ditch attempt by police to continue protecting her identity.

Suppression orders protecting the 46-year-old’s identity lifted at 4.15pm on Friday by order of the Victorian court of appeal, which last week ruled against an application by Victoria police and Gobbo’s lawyers to extend the non-publication order.

The decision was confirmed on Thursday by the high court, which earlier last month extended suppression orders until 12 April.

However, other details remain suppressed.

Victoria Police have spent more than $4m in legal fees trying to protect her identity, saying that her life and that of her family would be at risk if her identity were to be published. In November, the high court ruled that the risk to Gobbo’s life was real but did not outweigh the risk to the integrity of the justice system if her past clients were not informed that their lawyer may have breached legal privilege and worked against them.

The case sparked a royal commission into the management of police informants, which held its first directions hearing last month.

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The royal commission was among the organisations that pushed for the lawyer to be named, saying on Friday it would not be able to fulfil its terms of reference to determine the full scope of the scandal if she was not publicly identified.

“We are calling for submissions from individuals who were legally represented by [Gobbo] between 1995 and 2009 and who were found guilty or convicted, and sentenced,” the commissioner, Margaret McMurdo, said.

Gobbo was first signed as a police informant in 1995 when she was in the final year of her law degree at the University of Melbourne. She quickly built a career and a high public profile defending gangland figures, including Carl Williams and Tony Mokbel.

Police initially said she was signed as an informant in 2005. Her activities included wearing a police bugging device to record a conversation with former drug squad detective Paul Dale, for which she allegedly demanded payment of $20m. Dale was charged with the 2004 murder of police informer Terence Hodson but the charges were later withdrawn.

The extent of her work as an informer from 2005 to 2009 was exposed following an investigation by the Independent Broad-based Anti-corruption Commission (Ibac), following reports in the Herald Sun.

In a 2015 letter to assistant police commissioner Stephen Fontana, published in 2017 after a supreme court decision on the suppression of that Ibac report, Gobbo said she began assisting police “informally” in early 2004.

“What led me to do that was my own frustration with the way in which certain criminals (Carl Williams) were seeking to control what suspects and witnesses could and could not do or say to police via solicitors who were not in my view, acting in the best interests of their clients because of the undue influence and control of ‘heavies’ such as Williams,” she wrote.

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She said she was formally registered as Informer 3838 in September 2005, after she was “threatened by Tony Mokbel” to ensure that a first-time offender “kept his mouth shut” and pleaded guilty to drug charges linked to Mokbel’s drug syndicate.

Mokbel, 53, was jailed on drug-trafficking charges in 2007 and subsequently convicted.

He is one of 22 people, many of whom were Gobbo’s former clients, to receive a letter from the Office of Public Prosecutions in December informing them that their conviction could have been influenced by a breach of legal privilege due to her role as a police informant.

Mokbel is already reportedly considering an appeal.

Her uncle, former governor and retired supreme court judge Sir James Gobbo, released a statement to The Age distancing himself and his family from her actions, saying they have been “disturbed by the revelations” and that “no members of our immediate family have seen or spoken to Nicola in many years and have no knowledge of the matters to be investigated or her actions.”

At the first directions hearing of the royal commission last month, McMurdo said Gobbo was one of eight lawyers or legal officers – one of whom has since died – to provide information to police in the past decade. The others have not been named.

McMurdo said the use of lawyers to inform on their clients “has obvious potential to undermine the criminal justice system”.

Gobbo is expected to give evidence to the commission. Hearings are scheduled to begin late this month.