Former South Australian senator and lawyer Nick Xenophon has sued his former law firm for still using a “derivative of his name” in its new business title despite him leaving the firm last year.

Mr Xenophon filed a statement of claim with the Federal Court in March against XD Law and Advocacy Pty Ltd, formerly known as “Xenophon Davis Pty Ltd”.

The former senator is seeking for the business name to be changed by removing the letter X, and that the respondents pay his costs for the legal proceedings.

The law firm specialises in crime matters, advocacy and litigation in foreign jurisdictions, and has also provided representation for high-profile whistleblowers such as David McBride, Troy Stolz and Sharon Kelsey.

In the claim, Mr Xenophon said he “is and has been referred to as Mr X in numerous media articles, reports and broadcasts related to his legal and/or political careers”.

One example he cited was a June 2023 headline from news outlet InDaily, which stated: “Mr X still on the menu for SA’s most voracious lobbyists.”

Another article cited by Mr Xenophon, from News Corp in 2018, referred to a “new plan to be announced by SA Best Leader Nick Xenophon” and was headlined “Mr X vows to remove the gag orders under new whistleblower policy”.

Mr Xenophon was a senator for South Australia between 2008 and 2017 but resigned from his Senate seat to mount an ultimately unsuccessful bid to run for SA parliament.

An image from the firm’s Facebook page, from October 2020, showing Mark Davis and Nick Xenophon.(Facebook: XD Law)

The legal document also alleged that the firm’s existing partners Mark Davis and Natalija Nikolic breached a deed that was written up when Mr Xenophon left the firm, and that the firm is “engaging in conduct that is misleading and deceptive”.

Mr Xenophon’s claim states the deed required Mr Davis and Ms Nikolic to “cease using the applicant’s name and any identifying marks, symbols or images which associated their firm with [Mr Xenophon]”.

The former senator said that the “objectively implied intention” of the deed was that the two directors would cease using any “derivative”, “variation” or “truncation of the applicant’s name”.

“The letters ‘XD’ in the business name … [are] a conjoined and truncated version of ‘Xenophon Davis’ using each of the first and capitalised letters of those surnames,” the statement said.

Mr Xenophon also argued in the document that the firm was engaging in deceptive conduct by using “XD” in the business name because it was “implying a commercial association and affiliation” with him.

‘May be more productive speaking to Elon’

In a statement, Mr Davis — who is XD Law and Advocacy’s director — hit back at the claims, saying he utterly “rejects Mr Xenophon’s apparent belief that he owns a letter of the alphabet”.

“We wished him well and since he left we have made no attempts whatsoever to associate him with the firm,” Mr Davis said.

“Indeed, we have not made a single reference on any platform for more than 12 months.

“We dealt with his departure from the firm amicably but we now have a business to run.

“We will not be bullied by this. If he’s feeling particularly possessive about the letter X, it may be more productive speaking to Elon Musk.”

Mr Xenophon declined to comment on the case.