The attorney general has told his office to no longer post on X, making it the first UK government department to stop using the Elon Musk-owned platform amid increasing worries about its use to incite violence and racism.

Richard Hermer’s office last posted on X on Friday, and it is understood that officials have been told to no longer use the site, unless for the specific purpose of combatting disinformation there.

Downing Street has repeatedly defended the use by departments of a platform whose owner has called for the UK government to be overthrown and which is regularly criticised for promoting far-right and racist opinions, as officials say it is necessary to reach the public.

But the move by Hermer’s department is the first sign of change, as ministers increasingly worry about the impact of social media.

It is understood that Hermer made the decision after disorder in Southampton and Belfast earlier this month, and is increasingly worried about how X, more than other platforms, is being used by bad actors to attempt to divide communities.

He is also known to understand why other parts of government stay on the site, but has made the decision for his own department.

Eleven police officers were injured in widespread violence caused by people in Southampton who said they were protesting about the case of Henry Nowak, who was handcuffed as he lay dying from a stab wound after his killer called police and falsely claimed to have been the victim of a racist assault by the teenager.

Six days later, violence erupted in Belfast after far-right activists called for demonstrations in response to a stabbing attack for which a 30-year-old refugee from Sudan was charged with attempted murder.

One Northern Irish MP compared the disorder to a “pogrom” after the homes of people from minority ethnic communities were targeted for attack, and health workers were stopped on their way to work and questioned about their background.

In both cases, far-right agitators, often endorsed by Musk, called for protests and a furious response to the initial incidents.

Earlier this year, Keir Starmer threatened X with being blocked in the UK if it did not take action over a mass of sexualised images of women and children produced by its Grok AI tool, with X soon acting.

But after the Belfast riots, No 10 said any action would be left to Ofcom, the media regulator, which would mean nothing happening for around two months.

Ministers plan to amend the Online Safety Act to require social media firms to act more quickly to remove inflammatory content during riots or other crises, but this will not take effect until mid-July at the earliest.

In the meantime, the government will leave any official reprimand of X to Ofcom. The media regulator is awaiting a first quarterly report on compliance from the platform, but this is not due for at least two months.

On Monday Downing Street announced a ban on the use of many social media sites for under-16s, going further than a similar move enacted earlier this year in Australia.

Hermer is known to have been one of the cabinet ministers who has backed action against social media sites, including the ban for under-16s.

In a speech this week about what he said was the importance of maintaining Britain’s membership of the European convention on human rights, Hermer took aim at social media platforms.

He said: “We simply cannot let a very small group of crypto-funded millionaires of this world get away with using the debate about the ECHR or drawing closer to the EU to sow more division in this country – we cannot allow them to draw lines between our communities.”