At 1.05pm – shortly after the FTSE in London had closed down 1.4% and as media analysts were already floating the idea of a US recession or a “Trumpcession” – the president posted not about the economy but about Mahmoud Khalil, a pro-Palestinian activist and legal US resident whose arrest by immigration authorities on Saturday night stoked huge protest.

After a break of a few hours, another string of unadorned links appeared on Trump’s account, covering policies and obsessions including a nomination for the Nobel Peace Prize by a Republican in Congress, then embedded tweets of Republican support for him.

After US markets closed – with the S&P down 2.7%, the Dow Jones down 2%, the Nasdaq down 4%, and shares in Elon Musk’s Tesla seeing their worst day since late 2020, falling 15 points – Trump’s account was posting ads for The Apprentice, the 2000s reality show that rescued him from financial oblivion and set him out on the road to political power.

He later accused Canada of being “a Tariff abuser” and said“Elon Musk is ‘putting it on the line’ in order to help our Nation, and he is doing a FANTASTIC JOB!” while accusing leftists of “illegally and collusively” trying to boycott Tesla.

As usual White House officials had been speaking anonymously to media outlets, seeking to explain what the president really meant and to attempt to calm growing worries over economic chaos.

Speaking to CNBC, one official said: “We’re seeing a strong divergence between animal spirits of the stock market and what we’re actually seeing unfold from businesses and business leaders. The latter is obviously more meaningful than the former on what’s in store for the economy in the medium to long term.”

Michael Wolff, the author of four books on Trump, has described how many of the posts on his account are not made by the president but by Natalie Harp, a devoted aide whose closeness to the president has confused, angered and worried family members, according to Wolff.

Sarah Matthews, a White House communications aide in Trump’s first administration, has said in congressional testimony that it is “painfully obvious” when a tweet or social post is written by Trump himself because of “the phrasing of it, the capitalization of letters”. She added that messages sent by aides “seemed a little bit more grammatically correct”.

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