Johnny Depp Photo: IC

Johnny Depp walked into the hallowed halls of London's High Court three weeks ago seeking to expunge the stain of being branded a "wife beater" by The Sun tabloid.

But the 57-year-old will still have to win in the court of public opinion even if he comes out victorious once the star-studded trial ends Tuesday.

"I think the damage is done," said London PR agent and crisis consultant Mark Borkowski. 

"Even if he wins, it's going to be a Pyrrhic victory."

The legal odds would appear to be stacked in Depp's favor in a case dubbed "the biggest English libel trial of the 21st century."

England's ancient defamation law puts the burden of proof on the media and remains one of the strictest in the Western world.

The Sun's publisher and executive editor say they can back up their 2018 claim with 14 instances of the Pirates of the Caribbean hero abusing ex-wife Amber Heard.

Trial witnesses have contradicted each other repeatedly and defamation law expert Mark Stephens said Depp "would have to be a fool in a hurry" to lose the case.

Yet he and other consultants question the wisdom of Depp drawing global attention to one of the most controversial and self-destructive periods of his life.

Stewarts law firm partner Emily Cox said Depp might have felt he had no other choice.

"If left unchallenged in the internet age, this allegation would be attached to his name for the rest of his life," she told AFP.

Depp's dilemma

The Hollywood couple's troubled two-year marriage ended in a 2017 divorce that included a confidentiality clause prohibiting them from discussing their relationship in public.

High Court judge Andrew Nicol waved that provision to allow The Sun's legal team to use Heard's own words to back up its case.

The judge also forced Depp to face days of withering cross-examination in which the star admitted to only hazily remembering some events because he was consuming copious amounts of drugs.

"We are a crime scene waiting to happen," Depp wearily told Heard in one recorded exchange played in court.

Yet few of the sensational stories - including one involving feces in the couple's bed and another in which Depp scrawled messages on a wall with the bloodied stump of his severed finger while high - are new.

Most have been reported and the mystery surrounding how Depp lost and then found the tip of his finger is now part of Hollywood lore.

Some experts believe Depp can overcome the stories of drugs and debauchery - even if they cost him some future blockbuster roles.

But they doubt he can withstand the damage of failing to force The Sun to retract the wife-beating claim.

"An actor who suffers from or has suffered from substance abuse issues, and is open about this, will undoubtedly be better regarded than one implicated in domestic violence," said Cox.

Toxic fame

Heard has enjoyed a less lucrative career but has potentially even more to lose.

The 34-year-old's allegations emerged just as the #MeToo movement began exposing a history of sex abuse in film and media industry as a whole.

"She becomes a totem, an icon," said Borkowski. 

"She becomes a significant figure in the ongoing culture wars."

Stephens said Heard will "find it very hard to find work" if her story fails to convince the judge because her fan base and film credentials are so much smaller than Depp's.

"If The Sun loses, Heard could well find herself ostracized by those movements and by Hollywood," Cox agreed.

"If The Sun wins, Heard will likely be viewed as a brave crusader in the domestic violence and #MeToo arena."

The judge must read through a dozen volumes of evidence and is expected to take some days before delivering his verdict.

But Borkowski said he has already drawn his own conclusion from the case.

"To me it says one thing, both for Johnny Depp and Amber Heard and the whole process: Fame is toxic," said the legal expert. 

"Fame is a monster."