Mark Zuckerberg’s decision to ditch factcheckers on Facebook and “prioritise free speech” weeks before Donald Trump returns to power was condemned on Tuesday as a “major step back” for public discourse.

The Meta founder announced multiple changes to his platforms including Facebook and Instagram in an attempt to “dramatically reduce the amount of censorship”.

In a statement on Tuesday he said that, starting in the US, independent factcheckers would be replaced in the US by a system of “community notes” similar to that used on X, Elon Musk’s social media platform, which relies on users to add caveats and context to contentious posts.

Content moderation teams would also be moved from California to Texas “where there is less concern about the bias of our teams”, said Zuckerberg in a five-minute video statement that Nina Jankowicz, a former US government official tasked with fighting disinformation, described as “a full bending of the knee to Trump”.

Changes to the way Meta filtered content would also mean “we’re going to catch less bad stuff” while still taking seriously “a lot of legitimately bad stuff out there, drugs, terrorism, child exploitation”, Zuckerberg said.

He said factcheckers were “too politically biased” – an allegation strongly denied by factchecking organisations – and said Meta would “get rid of a bunch of restrictions on topics like immigration and gender that are just out of touch with mainstream discourse”.

The 40-year-old billionaire said the shift was in response to the US presidential elections, which he labelled “a cultural tipping point towards, once again, prioritising speech”.

Trump and Zuckerberg have had a rollercoaster relationship, with Trump threatening to jail the tech boss if he interfered in the election and then a November rapprochement with dinner at Mar-a-Lago and Zuckerberg donating $1m.

Trump said on Tuesday that the changes were “probably” in response to his warnings and added: “I think they’ve come a long way, Meta, Facebook.”

Last week it was announced that the former UK deputy prime minister Nick Clegg was stepping down as Meta’s president of global affairs to be replaced by the prominent Republican Joel Kaplan. Dana White, the chief executive of the Ultimate Fighting Championship and a prominent Trump supporter, was also appointed to the Meta board as the tech company prepares for Trump’s second term, which is set to have a major influence over technology companies through investment, subsidies and regulation, particularly of artificial intelligence.

But campaigners against harms caused via social media to women, children and ethnic minorities, as well as scientists, reacted to the news with dismay.

Global Witness, a human rights group, said: “Zuckerberg’s announcement is a blatant attempt to cozy up to the incoming Trump administration – with harmful implications. These changes will make it more dangerous for women, LGBT+ people, people of colour, scientists and activists to speak out online, where they already face disproportionate harassment and attacks.”

The Centre for Information Resilience, an organisation whose activities include tracking online hate speech and disinformation based on people’s gender ethnicity and sexuality, warned it was a “major step back for content moderation at a time when disinformation and harmful content are evolving faster than ever”.

Ian Russell, the father of Molly Russell, 14, who took her life after viewing thousands of images promoting suicide and self-harm on social media, including Instagram, said the moves “could have dire consequences for many children and young adults”.

He said he was “dismayed that the company intends to stop proactive moderation of many forms of harmful content and to only act if and when a user complaint is received”.

Meta said content about suicide, self-injury and eating disorders would still be considered “high-severity violations” and it “will continue to use our automated systems to scan for that high-severity content”.

The UK TV host Piers Morgan reflected a seam of support for Meta’s move when he welcomed it as “a complete U-turn on all woke censorship & cancel culture bullsh*t”.

The co-chairs of Meta’s oversight board, including the former prime minister of Denmark Helle Thorning-Schmidt, said in a statement: “We look forward to working with Meta in the coming weeks to understand the changes in greater detail, ensuring its new approach can be as effective and speech-friendly as possible.”

They added: “It is essential that decisions on content are taken with maximum input from voices outside of Meta, including of the people who use its platforms every day.”

In London a spokesperson for the prime minister, Keir Starmer, declined to be drawn on Zuckerberg’s remarks but stressed the UK had its own protections in the new Online Safety Act.

“Our relationship with the US across a number of areas is a very important one,” they said, adding: “Our online safety provisions coming in March are among the strongest on offer.”

Angie Drobnic Holan, the director of the International Fact-Checking Network which certified the factcheckers used by Meta, denied factcheckers had been biased and said: “That attack line comes from those who feel they should be able to exaggerate and lie without rebuttal or contradiction.”

Chris Morris, the chief executive of the UK factchecking organisation Full Fact, which has been funded by Meta to check Facebook content, called the announcement “a backwards step that risks a chilling effect around the world”. He said his organisation’s factcheckers assessed claims “from all political stripes with equal rigour, and hold those in power to account through our commitment to truth”.

“Locking factcheckers out of the conversation won’t help society to turn the tide on rapidly rising misinformation,” he said.

Zuckerberg said removing some restrictions on content on topics such as gender and immigration would “make sure that people can share their beliefs and experiences on our platforms” and said the focus of filters that scanned posts for policy violations would be shifted to only tackling illegal and high-severity violations.

“By dialling them back, we’re going to dramatically reduce the amount of censorship on our platforms,” he said. “We’re also going to tune our content filters to require much higher confidence before taking down content. The reality is that this is a tradeoff. It means we’re going to catch less bad stuff, but we’ll also reduce innocent people’s posts and accounts that we accidentally take down.”

He said Meta would “work with President Trump to push back on governments around the world that are going after American companies and pushing to censor more”.

He cited Europe as a place with “an ever-increasing number of laws institutionalising censorship and making it difficult to build anything innovative” and said: “Latin American countries have secret courts that can order companies to quietly take things down.”