Deputy Opposition Leader Julie Bishop “absolutely” stands by her claim she has never had a relationship with a client, despite attending a legal interview with her current partner (and former Perth lord mayor) Peter Nattrass in relation to how he obtained information on the criminal record of a council candidate.

Bishop led the opposition’s prolonged attack on Julia Gillard this week over her role in establishing a slush fund with then-partner Bruce Wilson in the 1990s. On Tuesday, Bishop told the media that unlike the Prime Minister she had never had a relationship with a client.

Crikey spoke with Bishop today in relation to published claims she had acted for Nattrass — with whom she is understood to have been in a relationship since 1995-1996 — in 2002. Contemporary reports indicate Nattrass was involved in an official investigation into how he obtained information about the criminal record of Terry Maller, a candidate for the Perth City Council. The information was allegedly leaked.

Bishop admitted she attended an interview with Nattrass: “On one occasion he was invited to an interview with the authorities , and I attended as an observer like, you know, somebody goes to the police station to give a statement and they’re accompanied.

“I didn’t act as a solicitor at that time, he was entitled to have somebody present and I went.”

Bishop insists she offered Nattrass no legal advice — she had ceased acting as as solicitor in 1998 when she went into Parliament and her practising certificate had lapsed.

Speaking on some of the allegations circulating about her past as a lawyer, Bishop said: “Honestly, where do you get this crap from? Look, it’s not your issue and you’re doing your job, I know that. But honestly, the desperate levels that people will go to to try and equate my conduct and my ethical standards with Julia Gillard’s is laughable.”

Bishop and Opposition Leader Tony Abbott have consistently emphasised they think Gillard’s history as a lawyer is relevant and important, arguing it goes to her character, competence and ethics as a political leader.

Crikey also asked Bishop whether she had been in any way involved in the legal affairs of her former partner (and former WA Liberal senator) Ross Lightfoot. Bishop is understood to have commenced a relationship with Lightfoot after her divorce in 1988. At the time she was a partner in the Perth branch of Clayton Utz (formerly Robinson Cox).

At one point there were allegations Lightfoot appeared to be a director of two companies (A-CAP and Coolkalg Resources), which were in the hands of receivers and liquidators. There are claims the AFP investigated the affairs of the companies. There are also claims then-senator Lightfoot used a taxpayer-funded study trip to China to negotiate deals for A-CAP, which led to a complaint by then-ambassador to China Ross Garnaut.

There is no evidence Bishop acted legally for (or provided legal advice to) Lightfoot — she told Crikey she never provided legal advice to him. When asked if he was ever a client of her firm, she said: “That’s a question for Clayton Utz … I have not acted for him.” When asked if her firm acquired any of his assets, she said: “Not to my knowledge.”

Bishop says Lightfoot “had his own family lawyer” in relation to his divorce with Sue Walker.

The Liberals’ deputy leader confirms she stated earlier this week she had never had a relationship with a client and she “absolutely” stands by that statement.

She says the crucial point she was making is Gillard was in a relationship with someone in a way that, Bishop claims, put Gillard’s firm in a position of conflict. Bishop says her point was that in assisting Bruce Wilson, Gillard was acting to the detriment of her firm’s client, the AWU.

“I’m not saying that lawyers cannot have a relationship with someone to whom they provide legal advice, but … they cannot provide legal advice to their partner which puts their firm in a position of a conflict of interest with another client, and that’s what Julia Gillard did, she put her firm in an impossible, untenable position of conflict of interest,” she said.

There is no suggestion Bishop may have provided legal advice or representation to someone with whom she was in a relationship, in a way that presented a conflict of interest to her employer.

“All I can say is I am proud of my legal career, I acted professionally and ethically at all times,” Bishop told Crikey. “I am happy to answer legitimate questions about my professional conduct over 20 years in the law.”

Critics of Bishop have also raised questions about her work as a solicitor acting for mining giant CSR in asbestos cases. Bishop has strongly rejected any wrongdoing on her part.