As world leaders gathered to discuss the grave threat posed by climate change, much was made about the need to control emissions. 

Now it has been revealed that at least one high-profile participant was reportedly unable to practice as he preached. 

US President Joe Biden audibly broke wind during the COP26 event - and while he was speaking with Camilla Parker Bowles, the Duchess of Cornwall. 

A source told the Mail on Sunday that Camilla has not been able to stop talking about the ageing President's "long fart" since he unleashed it in her company last week. 

"It was long and loud and impossible to ignore," the source told the outlet. "Camilla hasn't stopped talking about it." 

Biden met the duchess during a reception attended by Prince Charles, Prince William and Boris Johnson. 

It was a tough day for Biden, who had earlier nodded off during opening remarks at the climate change conference. 

The 78-year-old closed his eyes for 22 seconds before an aide appeared to jolt him awake. 

The day after his gaseous faux pas, Biden's administration launched a plan to reduce methane emissions, a potent greenhouse gas that contributes significantly to global warming. The announcement was part of a broader effort with the European Union and other nations to reduce overall methane emissions worldwide by 30 per cent by 2030. 

Clamping down on methane flaring and leaks from oil wells and gas pipelines — the focus of the Biden plan — is considered one of the easiest ways to cut emissions. 

Reducing methane from agriculture, in particular by belching cows, is a trickier matter. 

The impact of presidential poots and potential methods to restrict them remains unknown. 

- Additional reporting, AP