Organisers of the London Marathon are planning for the event to go ahead amid fears it could be cancelled because of the coronavirus outbreak.
A statement from London Marathon Events, which manages the annual race, said the latest government advice was that all mass events should still go ahead.
Cancellation of the event, which is due to take place on 26 April, would be of concern to the hundreds of charities that collectively raise tens of millions of pounds from the race each year.
Last year’s event raised a record £66.4m for charity, the thirteenth year in a row it has broken the world record for the highest amount raised by an annual single-day fundraising event.
The London Marathon has generated charitable donations of more than £1bn since it was first staged in 1981.
Marathons in Paris and Barcelona, which were both due to take place over the next month, have been postponed because of concerns about the spread of the coronavirus.
Fears have been expressed that if the London event is cancelled people might try to run the route anyway but without the usual medical support that is on hand during the full race.
Asked if organisers had any plans in place to reschedule the event for later in the year if it was cancelled, a spokesman for London Marathon Events said he was unable to speculate.
A London Marathon Events statement said: “We are monitoring closely the developments relating to the spread of Covid-19 and noting the updates and advice given by the UK government, the World Health Organisation and other UK public bodies.
“The government’s current advice is that all mass events should still go ahead.
“There are many mass events scheduled in the UK before us and we are working closely with the Department for Digital, Culture, Media and Sport and other mass event organisers to coordinate and agree appropriate advice to the public.”
Oliver Dowden, the culture secretary, said on Monday that it was “very premature” to talk about cancelling mass sporting events in the UK.