More than 40,000 runners have taken to the streets of the capital today to run what is set to be the hottest London Marathon on record.
The mercury could soar as high as 23C on Sunday for the 38th edition of the race.
Although the Met Office predicted rain in the afternoon, the morning, when runners will set off, is when temperatures are set to peak.
Runners have been advised to drop their goal-times and organisers have added more ice, water and run-through shower stations along the 26.2-mile course.
Guidance was also issued to runners planning on running in fancy dress outfits, asking them to think carefully if this was still appropriate.
Every 2-3C rise in temperature…