Forecasters have warned that thousands of people taking part in this year’s London Marathon could get wet in heavy rain.
The Met Office has predicted a “very wet” Sunday in the capital, with a more than 50% chance of rain through a nine-hour window from 7am to 4pm.
Jonathan Voutre, a spokesman for the forecaster, said runners would experience temperatures of around 10C.
He added: “More persistent rain has been pushing across south-east England throughout the day – which could provide for a relatively wet and damp London Marathon.
“You won’t see temperatures over 9 or 10C across the South.”
Sunday’s race is set to be the biggest London Marathon ever, with at least 45,000 people taking part in the mass participation event, up from 40,643 in 2022.
It includes runners classified as non-binary for the first time, including 118 people who identified as gender-neutral on their entry forms to take up the challenge.
Organizers have said it is part of an effort to make the race “the most diverse, equitable and inclusive marathon in the world”.
He added that LGBTQ-friendly “carnival energy” would be channeled over the 250-meter leg just before the 21-mile mark on Butcher Row, which has been renamed Rainbow Row for the event.
The stretch was projected to take place in 2022, and the directors have said it will be “bigger and better this year”.
Women will be able to access free sanitary products during the race for the first time and use ‘peequels’ – female urinals which have been trialled at music festivals including Glastonbury.
Famous faces taking part include The Crown star Josh O’Connor, and Mumford & Sons frontman Marcus Mumford, who is raising money for the Grenfell Foundation.
Former and current EastEnders cast members will also take on the challenge in memory of Dame Barbara Windsor, raising money and awareness for Alzheimer’s Research UK.
A total of £60 million is expected to be raised for charity.
Great Ormond Street Hospital (GOSH) Children’s Charity is the official charity of the year, and will use the partnership to launch its fundraising appeal for the new children’s cancer centre.
Sir Mo Farah, 40, who has a personal best of 2:05:11, will be among elite marathon runners for the last time, and he admitted there may be tears after the race.
The world’s fastest marathon runner, Eliud Kipchoge, 38, from Kenya — who holds the record of 2:01:09 — will not compete this year but is the official starter for the elite men’s race and mass participation event at 10 a.m.
Marathon record holder Brigid Kosgei, 10km record holder Yelmzaref Yehulav, and Olympic champion Peres Jepchirchir will be among those participating in the women’s race.
The women’s record is in the name of Kenya’s Kosgei with 2:14:04.
Runners will begin the 26.2-mile route from Greenwich Park, passing London landmarks including Tower Bridge and Trafalgar Square, before crossing the finish line near Buckingham Palace.
The event coincides with a nationwide trial of the government’s new public alert system, which will send a loud alarm to millions of mobile phones across the UK at 3pm.
Meanwhile, up to 50,000 Extinction Rebellion (XR) activists will be on the streets nearby for the third day of a protest called “The Big One”.
Members of climate groups have said they are coordinating with the organizers of the race and they do not plan to disrupt it, although spectators have been warned to avoid Parliament Square.
The elite race and public participation event will be broadcast live on the BBC from 8.30am, as well as on Red Button and iPlayer.