A High Court judge overseeing a trial featuring a businesswoman and Barclays, which is being broadcast online because of the coronavirus crisis, has said he will take no further action over the tweeting of a screenshot of the hearing.

Mr Justice Waksman, who is hearing evidence in a £1.6 billion case involving Amanda Staveley at the High Court in London, issued a warning on Friday after lawyers told that him a screenshot of proceedings had been tweeted by someone watching online.

The judge said on Monday that he had received an apology from the person responsible and would take no further action.

He had warned on Friday that taking photographs of court hearings was an offence and said the same rules applied to hearings being broadcast online because of the health crisis.

Ms Staveley says her private equity firm, PCP Capital Partners, was not treated fairly and is owed money for work it did setting up a Middle East investment deal with Barclays during the global financial crisis in 2008.

PCP is suing the bank and wants £1.6 billion damages. Barclays disputes PCP’s claim and says it is made of “sand”.

The trial, which began on June 8, is expected to last two months. Ms Staveley is currently giving evidence.

Limited numbers of people have been allowed to gather in court because of social distancing rules, and the trial is being shown on a webcast.

An on-screen warning tells viewers: “By viewing the webcast you accept the privacy policy and agree not to take any unauthorised recording or screenshot of the trial.

“It is a criminal offence to record, publish and take pictures of any court hearing without authorisation, including making, or attempting to make, an unauthorised recording or transmission of an image or sound being transmitted through a live video or audio link.”

Legislation which is nearly 100 years old bans the taking of photographs in court hearings.

The 1925 Criminal Justice Act says “no person” shall “take or attempt to take in any court any photograph, or with a view to publication make or attempt to make in any court any portrait or sketch, of any person”.

Senior judges have ruled that the taking of photographs in court can also be a contempt of court.

Trials are currently regularly being conducted virtually because of coronavirus, and legislation recently introduced also makes taking screenshots an offence.

The 2020 Coronavirus Act says: “It is an offence for a person to make, or attempt to make – (a) an unauthorised recording, or (b) an unauthorised transmission, of an image or sound which is being broadcast.”