An estimated 37,500 fun runners, amateur athletes, celebrities and elite sportsmen and women are taking part in the Virgin London Marathon.
Kenya's Wilson Kipsang won the elite men's marathon and Mary Keitany, also from Kenya, defended her title.
The men's wheelchair race was won by David Weir, his sixth victory, and Britain's Shelly Woods won the women's event.
Today's race, which remains the world's largest annual fund-raising event, was the last chance for elite British runners to claim a place in this summer's Olympics.
Only one man, Scott Overall, has so far qualified for Team GB and he was the official London Marathon pace maker.
Meanwhile, Sri Lankan participant Anuradha Indrajith Cooray was able to surpass the Olympic qualifying timing during his run.
Anuradha now qualifies for the Marathon at London 2012.