Boris Johnson knocked over a child during a game of street rugby in Japan.
The mayor of London took out the 10-year-old schoolboy as he raced down the mini turf pitch in Tokyo.
Toki Sekiguchi hit the ground and suffered some pain but was soon up and running again.
He said: “I felt a little bit of pain but it’s OK.” The schoolboy said it had been “enjoyable” meeting the mayor.
Mr Johnson, a keen rugby fan, was hurtling down the pitch at speed with the rugby ball when he ploughed into the little boy.
After they had picked themselves up, the mayor went over to Toki and asked if he was OK before shaking his hand.
“I’m so sorry,” he added.
The pair later posed for photographs and Mr Johnson handed over a 2015 rugby ball to the youngster.
It is not the first time Mr Johnson has collided with a youngster on the sportsfield.
Last year he sent a nine-year-old tumbling to the floor during a football match.
The mayor had been taking part in the friendly as part of an initiative to get more children involved in sport.
But Mr Johnson tripped up the child, sparking cries of “referee” from the crowd.
In a speech to the British and American chambers of commerce in Tokyo on the benefits of major sports events, Mr Johnson admitted that he had “flattened” the young boy and used the incident to draw parallels with the ups and downs of hosting the Olympic Games, which will be staged in Japan in 2020.
“We have just played a game of street rugby with a bunch of kids and I accidentally flattened a 10-year-old, on TV unfortunately,” he said.
“But, he bounced back, he put it behind him, the smile returned rapidly to his face.
“That is my theme tonight – the possibility that confidence can suddenly and unexpectedly return.”
He warned the business leaders there would be a mood of “gloom” in the run-up to the Games but said it would lift.
“For about a month Britain was crop-dusted with serotonin and the Games themselves were utterly spectacular,” he added.
Mr Johnson admitted he “did feel terrible about it” but said “that is what rugby is like” as he praised Toki for his quick recovery, which he described as”inspiring”.
“Poor little guy, I hope he is all right,” he said. “He seemed very cheerful afterwards. He bounced back. That’s a metaphor for life. “In the words of Chumbawamba, you get knocked down then you get up again. Obviously, I’m a bit out of practice, if I ever was in practice.”
“There can be no possible excuse except to say that is what rugby is like,” he added.
But he dismissed suggestions that the episode had eclipsed the more serious side of his trade mission to Japan.
“Don’t forget that what you are also doing is getting home to loads and loads of people in Japan that there’s a London delegation here that loves Tokyo, that is fascinated by Japan and is bringing British business people here and is interested in their city and interested in making contacts and that British people are full of admiration for Japan after their highly successful Rugby World Cup.
“So, there are all sorts of ways of getting the message across in a trade mission like this.”