LONDON (AdAge.com) -- Martin Sorrell took the stand this afternoon in London's High Court and will testify again tomorrow in the libel action the WPP Group chief executive brought against former WPP Italy executives Marco Benatti and Marco Tinelli involving e-mails, a "vicious" photo and a blog.

Courtroom cleared
Mr. Sorrell caused an uproar in the courtroom when he testified that the former wife of Mr. Benatti called to warn him that Mr. Benatti had threatened to kill him. The judge cleared the courtroom of journalists and was closeted in a closed session with both sides' legal teams for about half an hour this afternoon.

The libel trial opened yesterday as Desmond Browne, the prominent London barrister representing Mr. Sorrell, outlined his case in court: Mr. Sorrell fired Mr. Benatti in January 2006 as country manager for Italy, for alleged misconduct that is the subject of other legal action between the two men. Last March, Mr. Browne said, "there started being dispatched a series of e-mails containing a vicious JPEG image grossly intruding into the private lives of Sir Martin and Miss [Daniela] Weber." Ms. Weber, the former chief operating officer of WPP Italy, was closely associated with Messrs. Sorrell and Benatti.

Mr. Browne said Mr. Tinelli, who clashed with Mr. Sorrell when Mr. Tinelli was president-CEO of the FullSix media company started by Mr. Benatti and partly owned by WPP, "was directly involved in the dissemination of that vicious image and ... felt just as bitterly hostile [toward Mr. Sorrell] ... as did his boss, Mr. Benatti." As proof of that, Mr. Tinelli referred to Mr. Sorrell and Ms. Weber as "the mad dwarf and the nympho schizo," Mr. Browne said.

Wouldn't describe pic
Mr. Browne also said the e-mail was sent from a Yahoo France e-mail account under a false name set up from an IP address registered to FullSix France. Tantalizingly, Mr. Browne said it would be intrusive to even describe the picture, calling it vicious. That didn't stop the U.K. press from speculating wildly about the image, and the judge opened the trial today by scolding several journalists by name. Speculation about the image later disappeared from several papers' websites.

Normally a U.K. libel trial would be held in front of a jury. Mr. Sorrell's case is being heard only by a judge because the evidence digs deeply into the online world of blogs, e-mail attachments and memory sticks, said a courtroom observer. That raised concerns that a jury wouldn't grasp all the internet-related forensic evidence recovered from computers and elsewhere in cyberspace.

In fact, Mr. Browne segued from Shakespearean references to explaining to the judge how Outlook Express captures e-mail addresses as he opened his case yesterday. This morning, Mr. Browne told the judge how Wikipedia works, appearing to suggest that it would be easy to maliciously tamper with WPP's entry to insert negative information.

Missing memory stick
One key point revolves around a missing USB stick. "How is it that a USB stick onto which both the JPEG image and the distribution lists for the blog and the JPEG had been saved minutes before the first e-mails with JPEG went out ... found its way into [Mr. Tinelli's] laptop?" Mr. Browne demanded. "The USB stick which Mr. Tinelli says he cannot now find is a critical piece of evidence."

Mr. Browne, a specialist in U.K. media law and defamation, is squaring off against Mr. Benatti's barrister, Andrew Caldecott, an expert in defamation and malicious falsehood cases. Mr. Browne has appeared in high-profile cases like Elton John's libel suit against a U.K. newspaper.

Mr. Sorrell and Mr. Benatti, accompanied by an interpreter who translated everything into Italian, were in court today, but Ms. Weber did not appear.

The trial is expected to last three weeks, with Mr. Benatti testifying next week. A spokesman for Mr. Benatti declined to comment, and calls to both legal teams were not returned.