He is supposed to be committed to reducing emissions – but when President Joe Biden produced a little natural gas of his own at the COP26 summit, it was audible enough to make the Duchess of Cornwall blush.

An informed source has told The Mail on Sunday that Camilla was taken aback to hear Biden break wind as they made polite small talk at the global climate change gathering in Glasgow last week.

‘It was long and loud and impossible to ignore,’ the source said. ‘Camilla hasn’t stopped talking about it.’