Richard Lloyd ParryVerified account

A member of the Tokyo Olympic organising committee, Haruyuki Takahashi, says that he will bring up the possibility of a delay at a meeting of the executive board later this month. “We need to deal with it based on reality,” he told the Kyodo news agency. “Time is running out.”

But adjustments to the Games would be impossible according to Mr Masuzoe, who has intimate experience both of health crises and Olympic planning. As health minister in 2009, he led the country’s response to the H1N1 swine flu, which killed 42 people in Japan.

As governor of Tokyo from 2014 to 2016 he oversaw the early stage of planning and construction for the Olympics. He says that the chance of the Games going ahead unaffected by the coronavirus are very low.

Decision-making is complicated by the incubation period of the illness, up to a fortnight or even longer, compared to a few days for H1N1. This makes it impossible to make reliable predictions about the course of the pandemic.

The international character of the Olympics makes them vulnerable to conditions in countries other than Japan. “Think of South Korea, and also Italy, France, Germany and Iran,” Mr Masuzoe says. “Even if Tokyo is safe, athletes from other parts of the world cannot come.”

Postponement by less than a year will clash with busy schedules for other sports in which international broadcasters have already made investment. Holding the Games in 2021 or 2022 would upset the four year cycle on which sports federations all over the world operate.

Most of the Olympic audience, and its revenue, comes from the international television audience, so another possibility is to go ahead with the Games but to hold them in empty venues, thus preventing infection between spectators.

But this would be devastating for Tokyo, whose ¥597 billion (£4.5 billion) investment in the Games is justified by the economic boost imparted by hundreds of thousands of visitors.