The Foreign Secretary stalked off, saying he was not prepared to get into “a pub quiz about leaders around the world” with Sky News presenter Dermot Murnaghan.
Mr Johnson was being interviewed “down the line” for the channel’s Murnaghan programme when the contretemps occurred.
Initially, he was happy to respond when asked who the French foreign minister is - correctly identifying him as “mon ami” Jean-Marc Ayrault.
But when pressed to name the South Korean president, Mr Johnson appeared to be stumped.
“We are not getting into a pub quiz about the leaders around the world and I am going to, with great respect, invite you out to the pub Dermot so that we can take these conversations further,” he said.
“I have a terrible feeling that if I keep answering you, you’ll keep coming back with more. Have a good morning, see you.”
He then walked away from the outside broadcast camera, while in the studio, Mr Murnaghan replied: “Don’t you want enlightenment? You might be meeting her. Park Geun-hye, the South Korean president.”
The presenter then added to viewers: “One out of two ain’t bad.”