Over 38,000 fundraisers, amateur runners and elite athletes took part in the Virgin Money London Marathon on Sunday, making it the biggest in the event's 35-year history.
World record holder Paula Radcliffe, 41, completed her final competitive marathon in an unofficial time of 2:36:55 and an estimated 750,000 spectators lined the streets.
Radcliffe took part in the main event with the massed ranks rather than the elite field.
Her women's marathon world record of 2:15:25, set in London in 2003, is almost three minutes faster than any other woman has ever run.
After crossing the finish line, she told the BBC: "I didn't care about the time the whole way round. I was so tired.
"I wanted to try and thank as many people as possible."
She added: "You can't come to the London Marathon and not give it an honest effort."
Conditions were reasonably good for the runners, with patchy rain and mild temperaturesl.
British wheelchair athlete David Weir's bid for a record seventh Virgin Money London Marathon title ended in disappointment as he was pipped to the line by American Joshua George.
In the men's elite race, Eliud Kipchoge won a titanic tussle with fellow Kenyan Wilson Kipsang, crossing the finish line in
Ethiopia's Tigist Tufa ended Kenya's domination of the women's race with a shock victory in a time of 2:23:22.
Organisers said 38,020 runners crossed the start line this year, compared with the previous record of 37,227 in 2012.
Prince Harry was presenting medals to the winners of the elite races and meeting volunteers and members of the St John Ambulance.
Five politicians took time off from defending their House of Commons' seats in the General Election campaign to pound the streets of London.
The four Conservatives were minister for children and families Edward Timpson, Wales Office minister Alun Cairns, Graham Evans and Richard Drax.
Labour was represented by shadow justice minister Dan Jarvis.
A host of celebrities also tackled the famous 26.2-mile course.
They included Radio 2 DJ Chris Evans, TV presenter Jenni Falconer, Formula One driver Jenson Button, Radio 1 DJ Greg James, double Olympic gold medalist rower James Cracknell, fashion designer Henry Holland, Made In Chelsea star Oliver Proudlock and US model Christy Turlington Burns.
When asked how the race went, Cracknell, who finished in just over two hours and 50 minutes, said: "It's different to other races. Depending on which section, I would have a very different answer. The first part was all right, the middle part was very good and the end was horrible."
He raised money for brain injury association Headway after being injured in a cycling accident in the US in 2010.
"They helped me and my family out when I had an accident in America," he said.
"They support countless families and other victims so as well as raising money, hopefully people can understand the problem of a brain injury because it's an unseen illness."
Evans only announced today that he was taking part in the marathon.
"I just thought it was quite interesting to see if you can train for a marathon in secret, get away with it and maybe get round," he told the BBC.
Asked if he was aiming to finish in a particular time, he replied: "My plan is to get here, get round, get to see my wife and kids, get to the pub, get home and get on the radio tomorrow. That is it."
Falconer said she was proud to be raising money for charity at the event.
"You've got to remember who you're running for," she told the BBC. "I'm running for Cancer Research UK. There's a huge team of us out there.
"If you hammer that home in times of pain, when you're walking and struggling, just remember who you're running for."
The oldest entrant was Paul Freedman, 90, from Hornchurch, Essex, while the youngest was Jonny Innes from Falmouth, Cornwall, who celebrated his 18th birthday today.
Guinness received more than 100 requests from entrants attempting a new world record. These ranged from the fastest marathon wearing high heels to the quickest time dressed as a framed painting.
The races started at Blackheath and Greenwich Park with the finish line on The Mall.
Some £53.2 million was raised for charity at last year's event.