Individuals will have to prove they have suffered "serious harm" to their reputation if they want to bring a libel case into the UK after a landmark ruling by the country's highest court.

The Supreme Court on Wednesday ruled against the Independent and Evening Standard newspapers in a libel involving Bruno Lachaux over articles published in 2014 about his marriage breakdown and resulting from the articles caused him "serious harm".

However, it is a positive change that the 2013 Defamation Act has a significant change to the law and an "additional test" to those wanting to bring a claim.

It means that in future claimants must produce evidence that is important to an individual's reputation. It also confirms that for profitmaking entities to sue they have to show the harm caused serious financial loss. Judges will, however, still decide each case on its facts.

As part of the Lachaux appeal, the court has been asked to interpret the "serious harm" test contained in the 2013 legislation, which came into force in early 2014, and was designed to reduce the number of vexatious and trivial libel claims brought against publishers .

However, there is a lack of clarity on what constitutes a serious harm. The uncertainty comes as defamation claims filed in London increased 70 percent last year, rising from 156 in 2017 to 265 in 2018.

Caroline Kean, partner at media law firm Wiggin, said the ruling Supreme Court would make it more difficult to bring a claim.

"The balance has now swung back from the claimants in favor of the defendants. This is a very real victory for the media, "she said. "The Supreme Court has confirmed that the 2013 Defamation Act was intended to bring claimants bringing fatuous claims."

In his ruling, Lord Sumption said that the 2013 legislation did "introduce a new threshold of serious harm which did not previously exist".

A spokesman for ESI Media, which publishes both the Independent and the Evening Standard, said the company welcomed the decision. "It's a claim that has a claim for loss," he said.

"Whilst we are disappointed that the appeal is dismissed on the facts of this particular case, the question is only a preliminary issue. The Evening Standard and the Independent will continue to defend the claims brought by Mr Lachaux on the basis of the publication of the articles in the public interest.