Haugen told UK lawmakers how Facebook Groups amplifies online hate, saying algorithms that prioritise engagement take people with mainstream interests and push them to the extremes. She said the company could add moderators to prevent groups from being used to spread extremist views.

“Unquestionably, it’s making hate worse,” she said.

Haugen added that she was “shocked to hear recently that Facebook wants to double down on the metaverse and that they’re gonna hire 10,000 engineers in Europe to work on the metaverse,” Haugen said, referring to the company’s plans for an immersive online world it believes will be the next big internet trend.

“I was like, ‘Wow, do you know what we could have done with safety if we had 10,000 more engineers?’ It would be amazing,” she said.

It’s her second appearance before lawmakers after she testified in the US Senate earlier this month about the danger she says the company poses, from harming children to inciting political violence and fuelling misinformation. Haugen cited internal research documents she secretly copied before leaving her job in Facebook’s civic integrity unit.

The documents, which Haugen provided to the US Securities and Exchange Commission, allege Facebook prioritised profits over safety and hid its own research from investors and the public.

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Facebook CEO Mark Zuckerberg has disputed Haugen’s portrayal of the company as one that puts profit over the well-being of its users or that pushes divisive content, saying a false picture is being painted. But he does agree on the need for updated internet regulations, saying lawmakers are best able to assess the trade-offs.

Haugen has told US lawmakers that she thinks a federal regulator is needed to oversee digital giants like Facebook, something that officials in Britain and the European Union are already working on.

The UK government’s online safety bill calls for setting up a regulator that would hold companies to account when it comes to removing harmful or illegal content from their platforms, such as terrorist material or child sex abuse images.

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Facebook whistle-blower tells US Senate the social network can change but clearly not on its own

Facebook whistle-blower tells US Senate the social network can change but clearly not on its own

Collins was referring to the 2018 debacle involving data-mining firm Cambridge Analytica, which gathered details on as many as 87 million Facebook users without their permission.

Representatives from Facebook and other social media companies plan to speak to the committee on Thursday.

Ahead of the hearing, Haugen met the father of Molly Russell, a 14-year-old girl who killed herself in 2017 after viewing disturbing content on Facebook-owned Instagram. In a chat filmed by the BBC, Ian Russell told Haugen that after Molly’s death, her family found notes she wrote about being addicted to Instagram.

Haugen also is expected to meet next month with EU officials in Brussels, where the bloc’s executive commission is updating its digital rule book to better protect internet users by holding online companies more responsible for illegal or dangerous content.

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Under the UK rules, expected to take effect next year, Silicon Valley giants face an ultimate penalty of up to 10 per cent of their global revenue for any violations. The EU is proposing a similar penalty.

The UK committee will be hoping to hear more from Haugen about the data that tech companies have gathered. Collins said the internal files that Haugen has turned over to US authorities are important because it shows the kind of information that Facebook holds – and what regulators should be asking when they investigate these companies.

The committee has already heard from another Facebook whistle-blower, Sophie Zhang, who raised the alarm after finding evidence of online political manipulation in countries such as Honduras and Azerbaijan before she was fired.