"We have the infrastructure and the experience, and if I am elected I will make sure London is ready to host the biggest sporting celebration again, if we are called on in an hour of need."

But Yuriko Koike hit back at Mr Bailey, saying his comments were "inappropriate".

Tokyo 2020 organisers have set up a taskforce to work with public health officials to ensure the Games can go ahead as planned and the IOC has been advised by the World Health Organisation that there is no need to cancel or relocate the Games.

London held the Games in 2012 and Tokyo has been preparing to stage them since its winning bid was announced in 2013. Its plans have been disrupted by the outbreak of the coronavirus, which has killed more than 2,200 people and infected more that 76,000 around the world. A number of sporting events in Asia were forced to be cancelled.

Fears that the Games might be in jeopardy have grown since Japan confirmed that two people from the Diamond Princess cruise ship died of the virus and hundreds have been infected. While foreign passengers leaving the ship face more quarantine at home, Japanese citizens do not - a situation that has raised concerns about Japan's quarantine practices.

In London, officials played down Mr Bailey's comments. An official told the Japan Times that his remarks were "the remarks of a mayoral candidate, not the remarks of Britain or even London". The official insisted that London had no plans to stage the Games.

Last week, the chief executive of Tokyo 2020 attacked "irresponsible rumours" about Tokyo hosting the Games.

"With regards to the coronavirus, there are many irresponsible rumours but I would like to make it clear again that we are not considering postponing or cancelling the Games," Yoshiro Mori said.

"We would like to co-ordinate with the national government and act in a calm manner."