A 42-year-old man has died after collapsing at the finish line of the London Marathon.
The man, who has not been named, was given medical attention immediately after finishing the race, but was pronounced dead at hospital.
One of the women’s elite runners, Mami Konneh Lahun from Sierra Leone, has disappeared after finishing the race in 20th place.
Missing runner Mami Konneh Lahun (Metropolitan Police)
The 24-year-old is due to fly home later on Monday, but she did not return to her temporary accommodation in Greenwich, where she had been staying since April 7.
“Mami has no known links to the UK and is not in possession of a mobile phone,” Scotland Yard said.
Ms Konneh Lahun, who won the Sierra Leone and Liberia marathons last year, is believed to be her country’s fastest-ever female 5,000m and 10,000m runner.
An estimated 36,000 people took part in Sunday's race, the 34th London Marathon.
More than 1,200 volunteers from St John Ambulance lined the streets and medical staff advised runners to take on plenty of water and keep well hydrated as the race got under way under near-cloudless skies.
Temperatures of 11C (51.8F) were recorded at the start of the race in Greenwich at 10am, but as runners made their way around the 26.2-mile course through the capital the bright sunshine and lack of a breeze made conditions feel considerably warmer.
By the time runners reached the finish line in St James's Park temperatures reached 16C (60.8F), the equal highest of anywhere in the UK.
Kenyan world record holder Wilson Kipsang won the men's race in 2 hrs 4 mins and 29 secs, a course record, while home favourite Mo Farah came home almost four minutes back in 2 hrs 8 mins and 21 secs.
The women's title was taken by Edna Kiplagat of Ethiopia, in a time of 2 hrs 20 mins and 21 secs.
The death of the 42 year-old is the first fatality in the event since 2012, when 30-year-old hairdresser Claire Squires, from North Kilworth, Leicestershire, collapsed a mile from the finish line and died later from cardiac failure.
She was raising money for the Samaritans and in the week after her death donations to her fundraising website jumped from £500 to more than £1m.
A spokeswoman for Virgin Money, the event's organiser, said: "The organisers of the Virgin Money London Marathon would like to express their sincere condolences to the family and friends of the deceased.
"Our thoughts and deepest sympathies are with them at this difficult time."