“Congratulations @BorisJohnson on becoming the next Prime Minister of the United Kingston,” the US president’s daughter wrote on Twitter.
It was unclear whether she believed this is the country’s correct name or whether the tweet was simply the result of a misspelling.
The tweet came minutes after Mr Johnson was confirmed as the Conservative Party’s new leader. He will be named PM on Wednesday.
Amid an outpouring of derision online, Ms Trump deleted the post and re-shared it with the correct spelling.
Ms Trump, who is widely thought to harbour political ambitions of her own, is following a long tradition of misspellings by her father.
He has repeatedly become the target of ridicule after tweeting incorrect spellings including “seperation”, and “waite” (instead of wait).
Mr Trump had tweeted his congratulations to Mr Johnson too, but managed to spell the short phrase correctly.
“Congratulations to Boris Johnson on becoming the new Prime Minister of the United Kingdom,” he wrote. ”He will be great!”
Ms Trump removed her tweet without explanation as to how the mistake happened. She has repeatedly posted the phrase United Kingdom successfully on her Twitter account – including during last month’s state visit – and she has never tweeted the word Kingston before.
There is no such thing as the “United Kingston”, and the phrase does not appear to be used as the name for any major company or other organisation.
The tweet was posted using the Twitter client on iPhone, which does feature both an autocorrect and a suggestions feature. It is possible that Ms Trump mistakenly tapped the “s” button rather than the “d”, and that the phone presumed she was going on to write the word Kingston.
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