A 30-year-old woman collapsed and died while running in the 32nd London Marathon.
The woman, named on social networking sites as Claire Squires, fell to the ground in Birdcage Walk, near St James's Park, on the final stretch of the 26.2 mile course. She was treated by medical teams and taken to hospital, where she was pronounced dead.
The Daily Mail said Squires was a hairdresser from North Kilworth in Leicestershire who had raised more than £500 for the Samaritans.
"Hi guys, as you all know I am running the London Marathon. It was just going to be for fun, but it's a fab opportunity to raise money for my charity the Samaritans. If everyone I know could donate £5 that would be a great help and change lives," Squires wrote on her JustGiving page.
She died just a few hundred yards from the finish line on The Mall.
"We would like to emphasise that our immediate concern is for the family of the deceased. Our thoughts and deepest sympathies are with them at this difficult time," a statement on the London Marathon website read.
The event drew more than 37,000 runners. St John's Ambulance services said it treated 4,850 people, of whom 30 were taken to hospital.
Sunday's death was the 10th fatality since the event began in 1981. The last competitor to die was a 22-year-old fitness instructor in 2007.
The race was won by Wilson Kipsang and Mary Keitany from Kenya, who dominated the men's and women's events respectively.