The PM's former top aide Morgan McSweeney has told the BBC he found US President Donald Trump to be "much funnier than I expected him to be".
He said that during his first phone call with the PM Sir Keir Starmer, officials in the room had been "barely able to contain themselves" with a joke the president made about foxes eating birds killed by "windmills" - his preferred term for wind turbines.
"He went on to say that as the foxes ate so many birds and became lazy, they became fat, and as they became so fat people no longer knew what kind of a creature they were," he added.
Asked whether Trump had been trying to be funny, he replied: "Yeah, yeah, yeah. Yeah. Definitely."
