The Court of Appeal made the ruling this week because of what it described as the fundamental issues of trademark and advertising law raised by the case which require a European Union-wide answer.
The case stems from an ad run by 3 in 2004, which claimed its pay-as-you-go service was cheaper than O2's. The ad contained the "bubble" imagery synonymous with O2, which consequently took legal action, claiming the use of bubbles breached its trademark.
In March, the High Court rejected O2's claim, which the company took to the Court of Appeal. In his judgment, Lord Justice Jacob said the case raised an important question about how aggressive EU law permits advertising to be.
Giles Crown, a senior partner at the media law firm Lewis Silkin, which represented 3, said: "This judgment will be of great importance to advertisers across Europe, particularly in its restatement of key aspects of trademark and advertising law."
The European Court of Justice is likely to take several years before making a ruling.