The BBC has apologised to Japanese viewers after the country's embassy complained to the corporation over jokes broadcast on quiz show QI.
In an episode of the programme screened before Christmas, panellists joked about the experience of Tsutomu Yamaguchi, who survived both of the atomic bomb strikes towards the end of the Second World War.
Presenter Stephen Fry described Mr Yamaguchi, who survived the bombing of Hiroshima on August 6, 1945, and that of Nagasaki three days later, as "The Unluckiest Man in the World".
Around 200,000 Japanese people are believed to have been killed in the bombings and Mr Yamaguchi, who died last year at the age of 93, is the only person to have been recognised by the Japanese government as having survived both.
He was in Hiroshima on a business trip when the first bomb struck, leaving him with serious burns. The following day he returned by train to his home city of Nagasaki, which was bombed on August 9.
In the episode of QI, filmed in front of a studio audience, Fry asked the panellists, "Now what is so lucky about the unluckiest man in the world?"
He added: "Well, this man is either the unluckiest or the luckiest depending on which way you look at it."
Comedian Alan Davies, guessing Mr Yamaguchi's link to Hiroshima, said: "Bomb landed on him and bounced off?"
He later quipped: "He never got the train again, I tell you."
Japanese viewers who took offence to the jokes reportedly contacted diplomatic staff in London and emailed the show.