London Marathon: Thousands take part in 35th annual race
Tens of thousands of runners are taking part in the 35th London Marathon.
Organisers said more than 37,800 people are expected to complete the 26.2 mile course from Blackheath to The Mall, making it the biggest in the event's history.
Many competitors are raising money for charity and hoping to beat the 2014 record amount of £53.2m.
Paula Radcliffe, 41, a former winner and the current world record holder, is running her final marathon.
She started with the mass starters rather than the elite field for her final run along the course, on which she set the world record of two hours 15 minutes 25 seconds in April 2003.
Speaking to BBC Sport, Radcliffe said: "I want to do myself justice so obviously I won't be close to my fast time.
"It will be a totally different experience for me."
Three-time winner Radcliffe, who has had to nurse an Achilles problem just to make it to London, will be honoured with the inaugural John Disley Lifetime Achievement award at The Mall finish.
Organisers said about 37,800 runners started the race this year, compared with the previous record of 37,227 in 2012.
Competitors are running past some of London's most iconic landmarks including the Cutty Sark.
Home favourite David Weir, who was hoping to land a record seventh crown, finished second behind American Joshua George in the men's wheelchair race.
In the elite men's race Wilson Kipsang is hoping to become the fourth man to win three titles.
Many celebrities are running including Formula 1 star Jenson Button and Radio 1 DJ Greg James.
Athlete David Hemery, who won gold in the 1968 Olympic Games in the 400m hurdles, is running his first marathon for 39 years at the age of 70.
Some runners like Rob Young have given themselves additional challenges.
For Mr Young it will be his 367th marathon in a year having decided to run at least one marathon a day after watching last year's event.
The mother of the cancer fundraiser Stephen Sutton is also running her first London Marathon to keep a promise she made to her son before he died.
Jane Sutton said: "When I have been going out running he has been the person I am thinking about and hopefully I've got the same determination as him so I will cross that finish line."
Laura Harvey and Paul Elliott will be starting married life on the run by tying the knot halfway through the race.
Ms Harvey said: "We're both running separately halfway. We run to about Tower Bridge come off go to our venue, have a quick change to warm up, get married, have a few photos and then go to the end."
The oldest entrant is Paul Freedman, 90, from Hornchurch, Essex, while the youngest will be Jonny Innes from Falmouth, Cornwall, who is celebrating his 18th birthday.