LONDON — It began as an Instagram-related quarrel between the spouses of two British soccer stars and grew into a libel trial that provided a welcome distraction for a nation in turmoil.

The High Court on Friday brought an end to the long-running legal feud by ruling against the plaintiff, Rebekah Vardy, saying that she had not been defamed by her former friend Coleen Rooney.

In the verdict, Justice Karen Steyn ruled that the reputational damage suffered by Ms. Vardy did not meet what she described as “the sting of libel.” For that reason, she stated in a written decision published on Friday, “the case is dismissed.”

The court also chastised Ms. Vardy, who filed the suit against Ms. Rooney in June 2020, writing that she had regularly passed information about her onetime friend to the press, adding that “significant parts of her evidence were not credible.”

“There were many occasions when the Claimant’s evidence was manifestly inconsistent with the contemporaneous documentary evidence, evasive or implausible,” Ms. Steyn wrote in the decision.

With its combination of low stakes and high melodrama, the dispute between Ms. Vardy and Ms. Rooney did not amount to the trial of the century. But the case attracted months of overheated tabloid coverage at a time when Britain was navigating a stubborn pandemic and a struggling economy while its prime minister was on the ropes.

Ms. Vardy, the wife of the Leicester City striker Jamie Vardy, and Ms. Rooney, who is married to the former Manchester United star Wayne Rooney, belong to a group known as WAGs, a common, if sexist, tabloid acronym for the “wives and girlfriends” of professional athletes, particularly Premier League footballers.

In 2019, Ms. Rooney suspected that a follower of her private Instagram account was selling information about her, gleaned from her posts, to The Sun, a Rupert Murdoch-owned London tabloid known for its pungent celebrity coverage. To suss out the supposed leaker, Ms. Rooney set a trap: She made her Instagram Stories visible only to Ms. Vardy and used the account to plant false information about herself. Then she waited to see if it ended up in the press.

At the end of her monthslong sting operation, Ms. Rooney claimed that Ms. Vardy was the culprit. She leveled that accusation in a social media statement in the fall of 2019 that was widely shared. Because of her sleuthing tactics, Ms. Rooney became known as “Wagatha Christie,” a mash-up of WAG and Agatha Christie, the 20th-century mystery writer.

Ms. Vardy issued a swift denial that she was the leaker. She then said that she had hired forensic computer experts to determine whether anyone else had access to her Instagram account. After failed mediation, Ms. Vardy filed a defamation lawsuit against Ms. Rooney in High Court, which oversees high-profile civil cases in Britain.

This May, it went to court. The proceeding, formally called Vardy v. Rooney, became known as the Wagatha Christie Trial. The term was so common that it appeared in crawls on Sky News right next to “War in Ukraine.”

Tabloid photographers and cable news correspondents flocked to the steps outside London’s Royal Courts of Justice for the nine-day event, which proved to be a fashion spectacle as much as a whodunit.

Ms. Vardy, 40, arrived in an assortment of finery, including a buttery yellow tweed suit by Alessandra Rich and an Alexander McQueen blazer. On her left foot, Ms. Rooney, 36, wore a medical boot, an ungainly plastic device that she paired with a Chanel loafer, a Gucci loafer and a Gucci mule. She had sustained a fracture in a fall at her house.

Ms. Vardy testified for three days. “I didn’t give any information to a newspaper,” she said under questioning early in her testimony. “I’ve been called a leak, and it’s not nice.”

The trial had plenty of TV-worthy plot twists. It was revealed in court that laptops were lost and that WhatsApp messages between Ms. Vardy and her agent, Caroline Watt — which apparently disparaged Ms. Rooney — had mysteriously disappeared. Ms. Vardy’s lawyer added that Ms. Watt had “regrettably” dropped an iPhone containing WhatsApp messages into the North Sea. Ms. Rooney’s lawyer, David Sherborne, replied that the mishap seemed to have resulted in the concealment of evidence.

“The story is fishy indeed, no pun intended,” he said.

Ms. Vardy told the court she could “neither confirm nor deny” what exactly had happened to her missing digital data. At another moment, she began a response with the phrase “if I’m honest,” causing Ms. Rooney’s barrister to snap: “I would hope you’re honest, because you’re sitting in a witness box.”

The bits of false information that Ms. Rooney included on the Instagram account visible only to Ms. Vardy were not exactly earth-shattering. As part of her sting operation, Ms. Rooney claimed that she and her husband were going to Mexico for a “gender selection treatment,” because Mr. Rooney wanted their fifth child to be a girl. She also said that the basement of couple’s new house near Manchester, estimated to be worth $25 million, had been flooded. Those ersatz facts and others made it into The Sun’s coverage of all things WAG.

Although Ms. Vardy repeatedly said she had nothing to with the leaks — and went so far as to mount an expensive legal campaign in what turned out to be a futile attempt to prove her lack of involvement — the judge in the case was not impressed with her claims. In her analysis of Ms. Vardy, Ms. Steyn noted “a degree of self-deception on her part regarding the extent to which she was involved.”

The case drew so much media attention because WAGs — like the players on the “Real Housewives” franchise in the United States — loom large in the British cultural imagination. They are photographed constantly. They star in reality shows and have their own fast-fashion lines and false-eyelash businesses. A TV series inspired by their shopping habits, feuds and love lives, “Footballers’ Wives,” was a hit in the early 2000s.

WAGs had a breakthrough moment in 2006, when a group of them enlivened the staid resort town Baden-Baden during that year’s World Cup, which took place in stadiums across Germany. The ringleader was Victoria Beckham, who had risen to fame as Posh Spice in the Spice Girls before marrying the great midfielder David Beckham. Also on the trip: the 20-year-old Coleen McLoughlin, who was dating Mr. Beckham’s teammate, Mr. Rooney, and would later marry him.

The tabloids ate it up. Reports from Baden-Baden told of WAGs singing “We Are the Champions” from a hotel balcony, dancing on tabletops and chugging Champagne, vodka and Red Bull into the wee hours. In the daytime, the women went on epic shopping sprees and sunbathed as the paparazzi snapped away.

When England lost in the quarterfinals to Portugal, some sports pundits unfairly blamed the WAGs for the defeat. Predictably, the tabloids that had made them into celebrities tried to tear them down. “The Empty World of the WAGs” was the headline of a finger-wagging piece in The Daily Mail.

Years later, Wayne Rooney and Jamie Vardy played together for England, which added to the delicious awkwardness of the recent court proceedings.

The trial fit snugly into a culture that sometimes revels in images of how foolish it can be — see also the popular TV show “Love Island.” It also touched on betrayal and lies, which were defining themes in Britain as Prime Minister Boris Johnson incurred fines for breaking lockdown rules, then announced that he would step down after his party pushed him out over other deceptions.

The trial also presented the complexities of the British class system. Online jokes from those following the case homed in on Oxford-educated lawyers reading aloud text messages filled with profane terms from women who are often dismissed as shallow or “chavvy,” to borrow a word Ms. Vardy used in reference to a cousin of Mr. Rooney’s.

Unlike this year’s other high-profile celebrity court battle, Depp v. Heard, these proceedings were not streamed live, which added to the appeal. Old-school courtroom sketches made the parties look like a potato, the moon and, according to one commentator, “Norman Bates’s mother.”

The depictions gave the whole affair a lo-fi air, which was fitting, given that the joy of WAGs has always been how un-Hollywood they are. And in the recently concluded trial, Ms. Vardy and, to a lesser extent, Ms. Rooney delivered everything Britain ever wanted from WAGs — drama and back-stabbing, with designer bags swinging as they entered the fray.

For those who missed the trial or could not get enough of it, not to worry: The U.K. television network Channel 4 announced this week that it had planned a two-part docudrama based on the contretemps.