Johnny Depp’s defeat in the London libel courts has been hailed by domestic violence charities as a victory that should encourage other victims to come forward and seek justice.

The judgment on Monday by the high court that the Sun was justified in describing the Pirates of the Caribbean star as a “wife beater” was welcomed by lawyers and campaign groups who support those who have experienced domestic abuse.

The damage to the Hollywood actor’s reputation, following one of the most widely followed libel trials of the century, will be extensive. His lawyers said he was likely to appeal against the “perverse and bewildering decision”.

The four-week trial exemplified tactics used to silence and discredit victims, according to domestic violence charities.

In the 129-page ruling, the judge, Mr Justice Nicol, concluded: “The claimant [Depp] has not succeeded in his action for libel … The defendants [the Sun and News Group Newspapers] have shown that what they published in the meaning which I have held the words to bear was substantially true.

“I have found that the great majority of alleged assaults of Ms Heard by Mr Depp have been proved to the civil standard.”

The judge said he did not accept Depp’s characterisation of his ex-wife as a gold-digger. Nicol noted: “Her donation of … $7m to charity is hardly the act one would expect of a gold-digger”.

In 12 out of the 14 incidents of assault reported by Heard, the judge said he found the allegations proved. “I do not regard [the Sun’s] inability to make good these allegations [in the other two incidents] as of importance in determining whether they have established the substantial truth of the words that they published.”

Depp, 57, sued the Sun’s publisher, News Group Newspapers (NGN), and its executive editor, Dan Wootton, over an article published in the Sun that originally carried the headline “Gone Potty: How can JK Rowling be ‘genuinely happy’ casting wife beater Johnny Depp in the new Fantastic Beasts film?”

NGN relied on a defence of truth to the claim. The burden of proof was on the Sun to demonstrate that the story was substantially accurate on the balance of probabilities. This is the standard of proof in a civil case, whereas in a criminal case it relies on the matter being beyond reasonable doubt.

Depp’s lawyers had argued that the gravity of the allegations meant that the civil standard of proof applied in defamation cases should be applied “flexibly”, so that the more serious the allegation “the stronger must be the evidence before a court”.

Immediately after the ruling, the publisher issued a statement saying: “The Sun has stood up and campaigned for the victims of domestic abuse for over 20 years. Domestic abuse victims must never be silenced, and we thank the judge for his careful consideration and thank Amber Heard for her courage in giving evidence to the court.”

The US lawyer representing Heard in her forthcoming defamation case on similar grounds in the US, Elaine Charlson Bredehoft, said: “For those of us present for the London high court trial, this decision and judgment are not a surprise.

“Very soon, we will be presenting even more voluminous evidence in the US. We are committed to obtaining justice for Amber Heard in the US court and defending Ms Heard’s right to free speech.”

Jenny Afia, the solicitor at the London law firm of Schillings, which represented Depp, said: “This decision is as perverse as it is bewildering. Most troubling is the judge’s reliance on the testimony of Amber Heard, and corresponding disregard of the mountain of counter-evidence from police officers, medical practitioners, her own former assistant, other unchallenged witnesses and an array of documentary evidence which completely undermined the allegations, point by point. All of this was overlooked.

“The judgment is so flawed that it would be ridiculous for Mr Depp not to appeal this decision.”

Although Depp’s lawyers have indicated he is likely to appeal, it may prove difficult for them to overturn what are findings of fact by the trial judge. The judge’s rulings on those points are effectively similar to a jury’s verdict in a crown court. Appeals are normally on points of law.

Commenting on the decision, Caroline Kean, a partner at the London law firm Wiggin LLP, said: “This is a heartening and just decision which serves as a reminder that British libel laws are not there to curtail free speech and the media’s right to publish on stories of global interest.

“This case was effectively a forum for two private individuals to slug it out and a clear misuse of taxpayers’ money, taking up court resources that could have been deployed for more worthy causes.”

Lisa King, from the domestic violence charity Refuge, said: “This is an important ruling and one which we hope sends a very powerful message: every single survivor of domestic abuse should be listened to and should be heard. No survivor should ever have her voice silenced.

“A common tactic used by perpetrators of domestic abuse is to repeatedly tell victims that no one will believe them – and to use power and control to try and silence them. What we have seen today is that power, fame and financial resources cannot be used to silence women. That is a welcome message for survivors of domestic abuse around the world.”

Harriet Wistrich, the founder of the Centre for Women’s Justice, said: “So many women who have tried to speak out or share their experiences are being threatened with libel actions. This is a really helpful judgment and will serve as a warning to men who think they can silence those who speak out about their abuse.”

Nicki Norman, acting chief executive at Women’s Aid, said: “The allegations of domestic abuse against Johnny Depp were extremely serious. Everyone who has experienced domestic abuse deserves to be listened to and believed. This also applies to survivors who do not fit the image of the ‘perfect’ victim – and regardless of the high profile of the alleged abuser. There is no excuse for domestic abuse.”

Sarah Harding, a partner specialising in family law at Hodge Jones & Allen, said: “It is hoped that this case will encourage other victims of domestic violence to come forward and seek the protection that they need. In addition to the Me Too movement and the domestic abuse bill … this case will highlight that the courts do listen, regardless of wealth or stature.”