Facebook and Instagram owner Meta has agreed to pay up to 18 billion US dollars (£13.3 billion) as part of a settlement ending a legal battle in the US, where it will also introduce major new protections for teenage users.

The agreement resolves claims filed by 47 US states accusing the tech giant of designing Instagram with features that are addictive to children and teenagers and can harm their mental health.

It brings an end to a trial that kicked off last week in California and that had expected to see chief executive Mark Zuckerberg give evidence before a jury in federal court.

The settlement is viewed as one of the largest in state consumer protection history in the US.

Jay Jones, the attorney general for Virginia, said: “For years, Meta intentionally deceived the public about the addictive and harmful design features that have wreaked havoc on youth mental health.”

He said the settlement would “put an end to these dangerous practices and deliver meaningful relief that will protect children from online harm”.

Meta unveiled a set of new protections and controls that will automatically apply to under-18s on Instagram and Facebook, subject to court approval and only for participating US states.

This includes a default night-time block, between midnight and 6am, muting notifications during school hours, hiding the number of “likes” and reactions on posts by default, and blocking teens from using extreme makeup filters.

Meta has also committed to strengthening tools to prevent underage accounts being created and protecting teenagers from harmful content.

These new measures will not apply to users worldwide, including the UK.

The total settlement will be made in instalments over 10 years to the US states involved.

But Meta called on rival social media platforms TikTok and YouTube to make similar changes to restrict teenage usage.

It warned that 30% of the settlement, amounting to about 5.2 billion dollars (£3.8 billion), would only be paid if YouTube and TikTok agreed to pay the same sum, and if they implement one-hour daily limits, night mode and age-assurance measures.

Meta’s chief legal office CJ Mahoney said its new protections for teenagers “will only work if all our peers join us”.

“Because teens move fluidly across dozens of apps, we need an industry-wide solution,” he said.

“As a parent, I’m proud of both the work Meta has done to protect kids historically, and of this new ground-breaking agreement.

“But its success depends on all other social media platforms following Meta’s lead.”

The Tories said the settlement showed social media companies have “have turned a blind eye to the damage being done”.

Shadow education secretary Laura Trott added: “Social media companies can no longer be allowed to freely harm our children.

“They should not have unfettered access to children until they can prove their platforms are safe. Today’s settlement shows that they are not.”

She has urged Prime Minister Andy Burnham to “get on with” a social media ban for under-16s, which is set to come into force next year, adding: “Every further delay leaves more children exposed.”

The Molly Rose Foundation – which was set up in memory of 14-year-old Molly from Harrow, London, who took her own life in 2017 after viewing harmful content – said the settlement “demonstrates that big tech can and should be held to account”.

Rowan Ferguson, senior policy and public affairs manager at the charity, added: “We have long been calling for action to address harmful and addictive design choices, underpinned by business models that prioritise profit over safety. This outcome demonstrates that, with the right motivation, change is possible.

“However, the denial of wrongdoing is disappointing, as it’s clear Meta’s business model has continuously failed to prioritise child safety. As the case has been cut short, we have been deprived of yet another opportunity to discover more about what Meta really knows about the harm it causes its young and vulnerable users.

“As these changes only apply to US users, the UK Government must heed this outcome and seize this opportunity to deliver a reset to children’s online safety across all platforms.

“Andy Burnham has now seen that it is possible to take on big tech to address drivers of online harm. It’s time for the UK Government to be brave, bold and decisive, in ways it hasn’t been before.”