Elon Musk has restored the X account of conspiracy theorist Alex Jones following a poll on the social media platform formerly known as Twitter that came out in favour of the Infowars host who called the 2012 Sandy Hook school shooting a hoax.

It poses new uncertainty for advertisers, who have fled X over concerns about hate speech appearing alongside their ads.

Mr Musk posted a poll on Saturday asking if Jones should be reinstated, with the results showing 70% of those responding in favour. Early on Sunday, Mr Musk tweeted: “The people have spoken and so it shall be.”

A few hours later, Jones’ posts were visible again — the last one from 2018 when the company permanently banned him and his Infowars show for abusive behaviour.

Mr Musk, who has described himself as a free speech absolutist, said the move was about protecting those rights.

In response to a user who posted that “permanent account bans are antithetical to free speech”, Mr Musk wrote: “I find it hard to disagree with this point.”

The billionaire Tesla CEO also tweeted it is likely that Community Notes — X’s crowd-sourced fact-checking service — “will respond rapidly to any AJ post that needs correction”.

Jones repeatedly has said on his show that the 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut, that killed 20 children and six educators never happened and was staged in an effort to tighten gun laws.

Relatives of many of the victims sued Jones in Connecticut and Texas, winning nearly 1.5 billion dollars (£1.2bn) in judgments against him.

In October, a judge ruled that Jones could not use bankruptcy protection to avoid paying more than 1.1 billon dollars of that debt.

Relatives of the school shooting victims testified at the trials about being harassed and threatened by Jones’ believers, who sent threats and even confronted the grieving families in person, accusing them of being “crisis actors” whose children never existed.

Jones is appealing against the judgments, saying he did not get fair trials and his speech was protected by the First Amendment.

Restoring Jones’ account comes as Mr Musk has seen a host of big brands, including Disney and IBM, stop advertising on X after a report by liberal advocacy group Media Matters said ads were appearing alongside pro-Nazi content and white nationalist posts.

They also were scared away after Mr Musk endorsed an antisemitic conspiracy theory in response to a post on X. The Tesla CEO later apologised and visited Israel, where he toured a kibbutz attacked by Hamas militants and held talks with top Israeli leaders.

But he also said advertisers are engaging in “blackmail” and, using a profanity, essentially told them to go away.

“Don’t advertise,” Mr Musk said in an on-stage interview late last month at The New York Times DealBook Summit.