The UK is set to defy Donald Trump over young people’s use of social media after the US warned against a blanket ban for under-16s.

In a response to the consultation on a ban, the US embassy in London said the country preferred “narrowly targeted requirements” for adult content “rather than broad social media bans”.

While the US said it did not “categorically oppose age assurance measures”, it said: “Most content should remain accessible by default, including political speech.

“We believe an open internet is essential to the preservation of free speech and most content should be accessible by default unless the provider knows or has reason to know the user is a child.”

It added that it was concerned that technology was not good enough to determine whether someone was under 16, and that the move could “impose disproportionate compliance burdens on American companies”.

Asked about America’s objections to a ban, Sir Keir Starmer’s official spokesman said the prime minister was “focused on what’s right for families here and now, and into the future”.

Earlier, technology secretary Liz Kendall said she would not be “swayed in any way, shape or form from doing what I believe is right for children in this country”.

She told Sky News she would read the US’s response “carefully” but was “much more bothered about the parents who have replied to the consultation”.

The consultation, which closed on May 26, received around 120,000 responses, making it the second-largest government consultation in history after a consultation on equal marriage in 2012.

Sir Keir told his Cabinet on Tuesday morning that the response “showed the strength of feeling about the issue” and said there was “no question” the Government would act.

Ms Kendall has said an Australian-style ban on under-16s using social media is “on the table”, along with other options such as curfews or limits on addictive features.

But ministers appear to be leaning towards a ban, with 90% of parents who responded to the consultation saying they would back one.

Conservative leader Kemi Badenoch has also repeatedly called for a ban, telling the BBC on Tuesday: “Social media is for adults, it’s not for children.”

And the Liberal Democrats have urged Sir Keir not to be “bullied into watering down protections for children online” by pressure from the US.