Britain's Olympic chief believes Japan will shoot up the medal table when it hosts the 2020 Summer Games in Tokyo, making it difficult for his own team to continue its rise.
Great Britain became the first nation to increase its medal haul at the Summer Olympics following the edition it hosted, when it won 67 medals at the 2016 Rio de Janeiro Games compared with 65 at the 2012 London Games.
But Sir Hugh Robertson, chairman of the British Olympic Association, says it will be very difficult for Team GB to improve yet again in Tokyo next year -- in part because he expects Japan to perform so well.
"It is absolutely possible to improve again in Tokyo, but I think for a number of reasons it will be a tougher games for us," Robertson said in an interview with Kyodo News in London.
"It's very hard to continue on the trajectory we are on at the moment, and I think the home team challenge in Tokyo is going to be very strong. We are expecting a very considerable challenge from Japan."
Great Britain finished second behind the United States at the Rio Games, and although China won 70 medals overall, their tally of 26 golds compared with Team GB's 27 saw them place third.
Japan finished sixth, with 12 golds and 41 in total.
Robertson's prediction of a strong Japanese performance chimed with a recent forecast by sports data company Gracenote Sports, which had Great Britain dropping to fifth with 14 golds and Japan jumping to fourth on 31 golds, with the United States, China and Russia occupying the first three places in that order.
"We had a generation of athletes who peaked for London, many of whom came around for one final go in Rio, and we have a new generation coming through now, but it can take a while to set in," Robertson said.
The former minister for sport and the London Olympics said he has been impressed with the preparations for the Tokyo games.
"We have a fantastic range of (pre-games) facilities and we are incredibly grateful for the welcome we've had in Tokyo and for the standard of the facilities," he said. "I think this is going to be a fantastic games. Tokyo is a city with a great and proud Olympic tradition."
"The Japanese can build fantastic facilities, with incredible ease, it seems. Everything that I have seen on my various visits there absolutely reinforces the view that this is going to be one of those epoch-making games."
In terms of the legacy potential of staging the Olympics, Robertson said the greatest opportunity is the chance to improve the host city's image.
"It gave this country a once-in-a-lifetime opportunity to rebrand how other countries see us -- I'm not sure that before 2012 our reputation for running things was as good as it was afterwards," he said.
"Now people understand that London is a multicultural city where everyone from around the world is represented, that it is a can-do, forward-looking place. People will absolutely look at Tokyo in the same way and say 'wow.'"
Robertson said that for the first time, Britain may send more female athletes than male to Tokyo, which he believes could provide a boost to sports participation among teenage girls.
He also had some advice for the International Olympic Committee in the wake of a series of drop-outs by potential host cities as fears of spiraling costs have scared off local populations.
"The Olympic Games get caught up in global politics and we're in an era where anti-establishment parties who have a 'don't trust what you're told' philosophy are having quite a lot of success," Robertson said.
"The Olympics shouldn't get caught up in this -- it's a global festival of sport -- but unfortunately it has done and the IOC possibly need to have a keener eye for that, because for years the IOC has tried to position itself as a global superpower. It's very close to the U.N., and so on. Perhaps it just needs to take itself back to its core mission, which is to run the world's best sports competition."
"I think if you begin to market it as just that, then quite a lot of these problems go away."
Robertson also offered his support to the World Anti-Doping Agency for its stance on Russia and rebutted the suggestion that the Sochi doping scandal had set back efforts to eradicate the use of performance-enhancing drugs.
"There have been more positive tests out of London than any games, but that is because we caught people. In a sense, I take great comfort from the fact more people are now getting caught and the ability of the international community to freeze samples.
"There is a whole generation of athletes who competed in the 80s who were denied medals because of an East German doping program. Those things can never be put right."
And while the ongoing turmoil caused by doping in Sochi is lamentable, Robertson said, he also takes comfort in Great Britain's four-man bobsleigh team officially moving up two places after Russian crews were disqualified and being awarded a post-games bronze "as 30 years ago they wouldn't have."
"That's part of why I support what WADA is trying to do with the Russian doping lab because they are trying to secure the samples that will enable them to retest everything," he said.
"That is how you detect the maximum number of dopers and can reallocate medals, whereas just banning them for ages without getting those samples would not be the right thing to do."