Optus has won a legal stoush over its "empires end" ads, with Victoria's Supreme Court rejecting Telstra's claims they amount to misleading or deceptive conduct.
The telco claimed Optus' use of the phrase wrongly implied it "undisputedly" operated Australia's best mobile network, but Justice Ross Robson was not convinced.
"I find that Optus' advertisement conveys the representation that Optus' mobile network is better than Telstra's, but not that it is 'undisputedly' better," the judge ruled on Wednesday.
He also overturned an interlocutory injunction granted two weeks ago, to stop Optus running the ads stating: "Empires end. That's what they do".
The ads also said: "The Optus Mobile Network has been ranked the best overall in voice and data", adding in fine print this was backed by the P3 Mobile Benchmark in December 2017.
Justice Robson rejected Telstra's argument the ads conveyed that the relative market positions of the two telecommunications giants had undergone a permanent change.
"It would be fanciful to imagine that the humorous image of a Telstra phone box in a desert landscape would persuade a reasonable person that Telstra's strong position in the market has been permanently destroyed," the judge said.
The telco earlier argued the ads should be taken down from billboards in Queensland, NSW, Victoria as well as from websites, as they ran the risk of convincing ordinary Australians to sign up with Optus, because Telstra no longer had the best mobile network.
But Optus said Telstra's analysis of the ads was "miles away" from what they actually conveyed.
"The words 'empires end' conjure up historical references," Neil Young QC previously said.
"It's not saying anything about the demise or obsolescence (of Telstra). It's a historical jest."
Justice Robson ordered Telstra to pay Optus' legal costs.