Their feud exploded into public view in October a year ago, when Rooney, whose husband is Manchester United's all-time leading scorer, posted a message explaining that she had become suspicious of one of her friends and had carefully planned and executed a sting operation.
Vardy's lawyers have argued the meaning of Rooney's post was that she had "consistently and repeatedly betrayed the defendant's trust over several years by leaking the defendant's private and personal Instagram posts and stories for publication in The Sun".
Today, the High Court ruled the post "clearly identified" her as being "guilty of the serious and consistent breach of trust".
He said: "The fact that these sting operation stories also then appeared in The Sun, after access to her private account was limited to just the @beckyvardy account, is the reason why the defendant published the post which is the subject of this claim".
Rooney is the wife of former Manchester United star Wayne Rooney, while Vardy's husband Jamie plays for Leicester City.
In a judgment today, Mr Justice Warby ruled that the "natural and ordinary" meaning of Rooney's posts was that Vardy had "regularly and frequently abused her status as a trusted follower of Ms Rooney's personal Instagram account by secretly informing The Sun newspaper of Ms Rooney's private posts and stories".More news: Pfizer and BioNTech will seek regulatory clearance of their coronavirus vaccine
In a ruling, High Court judge Mark Warby ruled that Rooney had clearly accused Vardy of leaking private Instagram posts to the tabloid. "Rebekah Vardy's account" - diluted the meaning. It would be a poor denouement if all that was being said was that the named individual was to be suspected of the wrongdoing but it might be someone else'. "The post then takes the form of a 'whodunnit"'.
He later said: 'There is nothing in these words, apart from the word "account", that in any way suggests that the behaviour of which Mrs Rooney is complaining might have been carried out by anyone other than the account holder, Mrs Vardy'.
"She has been drawn into this litigation despite the fact she has offered on a number of occasions to mediate with the claimant, Mrs Vardy. Whatever leaks there were did not come from her".
After a final tale was leaked to the media she claims was only visible by Vardy's account she went public with her allegations.
He said Coleen's message was "a considered post, using wording composed with some care".
Such was the reach of the story that some users responded to a Tweet by U.S. President Donald Trump in November 2019.More news: Mike Pompeo to meet Taliban, Afghan negotiators in Doha
Now, Coleen and her team must prove Becky was involved in a bid to win the lawsuit.
Mrs Rooney has denied any wrongdoing.
During their court hearing this week - which took place without Vardy or Rooney attending in person - lawyers for Vardy argued that Rooney's "detective process" in her Instagram post was "to find the true villain of the piece", and claimed "the finger is being pointed" at Vardy as a person, rather than her Instagram account.
"Mrs. Rooney intends to defend these words as true in whatever meaning".
Vardy is suing Rooney for damages in libel, however, a stay of proceedings was agreed today until February, with both legal teams hoping that a deal can be worked out that will prevent it going to full trial. A judge has made an initial ruling in favour of Vardy, but the legal battle is far from over.
"Coleen's defence to this misguided action was filed last month".More news: U.S. election: Reporter asks Donald Trump if he's 'being a sore loser'