Boris Johnson rested his foot on a piece of furniture during his visit to the Elysee Palace in Paris.
The prime minister was pictured in a relaxed pose as he spoke with Emmanuel Macron at the French president's official residence.
Mr Johnson's casual demeanour was branded "rude and embarrassing" by Sonia Purnell, a biographer of the former London mayor, amid criticism of his actions on social media.
"Imagine if Macron put his foot on the table at Buckingham Palace," she added on Twitter.
However, video footage of Mr Johnson's encounter with Mr Macron later suggested the prime minister's brief gesture was a shared joke as the t...
