Former federal attorney-general Christian Porter has lost his Federal Court battle over a ruling that saw him lose lawyer Sue Chrysanthou from his defamation case against the ABC.
Mr Porter took legal action against the ABC over a story about an unnamed Cabinet minister accused of an alleged historical rape.
Mr Porter revealed himself to be the subject of the allegations but categorically denied any wrongdoing.
However, the case was abandoned before it had time to start. Mr Porter settled against the ABC last year, with no damages paid.
But Mr Porter appealed a ruling that had been made separately to the main case.
Jo Dyer, a friend of the woman who made the allegation against Mr Porter, made a surprise challenge to his lawyer Ms Chrysanthou's role.
Ms Dyer said she had earlier sought some legal advice from Ms Chrysanthou about related issues and was concerned she had material from that consultation that might be used for Mr Porter's case.
The initial decision to restrain Ms Chrysanthou from being part of the defamation case cited the danger of misuse of confidential information received by her in dealings with Ms Dyer and the need to protect the integrity of the judicial process including the appearance of justice.
Mr Porter's lawyers argued she had done nothing wrong, that she had simply taken Mr Porter's case, under the "cab rank" rules, which obliged her to take the brief.
But Ms Dyer's lawyers argued Ms Chrysanthou had a duty to her first.
On Thursday, three Federal Court judges agreed, dismissing Mr Porter's appeal against the original decision to remove Ms Chrysanthou from his case.
The judgement is likely to mean Mr Porter will have to pay Ms Dyer $430,000 in costs.
The money has been in trust pending the outcome of the appeal.
