‘This was a righteous case. A holy war': the lawyer who took on Meta and Google – and won

When Mark Zuckerberg walked into a Los Angeles courtroom on 18 February flanked by an entourage bedecked in Meta Ray-Bans, some people laughed. If this was an attempt at product placement for the company’s newest range of smart glasses, it was jarringly ill-judged: Zuckerberg was about to testify before a jury in a landmark lawsuit that sought to prove that Instagram and YouTube are addictive by design, and he had passed a throng of bereaved parents on his way into the courthouse. But the prosecution team, led by Mark Lanier, were not laughing. This was a serious trial. For the first time, the most powerful names in social media were being held to account for the inherent design of their platforms, rather than the content hosted on them. They were accused of deliberately and maliciously building products that keep children hooked, with disastrous consequences for the mental wellbeing of young people. It was a landmark case – a big tobacco moment for big tech. But there were specific reasons why the prosecution was deeply disturbed to see Meta Ray-Bans in court. “We had fought hard for an anonymous jury. We didn’t want the names disclosed in a way where Google could go pull up their Gmails, where Meta could go pull up their Facebook accounts,” Lanier tells me in his warm Texas drawl. “Then Zuckerberg shows up with security g...