Tens of thousands of fun runners and amateur athletes set off in bright sunshine as the 32nd London Marathon got under way on Sunday morning.
Up to 37,500 athletes are expected to finish the 26.2-mile course through the streets of the capital to earn their marathon medals and raise money for countless charities.
Mary Keitany retained her Virgin London Marathon title, winning the women's race in a time of 2:18:36. The long distance runner set a new personal best and a Kenyan record in the process.
Wilson Kipsang of Kenya later won men's elite race at his first attempt. The reigning Frankfurt Marathon champion beat compatriot Martin Lel into second. Ethiopia's Tsegaye Kebede was third.
Briton Shelly Woods won the women's section of the London Virgin Wheelchair Marathon, coming in at 01:49:10.
As well as the elite athletes and fun runners, a host of celebrities crossed the start line in support of good causes.
London Marathon 2012 In Pictures
Newsreader Sophie Raworth, 43, revealed she is running in aid of St John's Ambulance after collapsing during last year's event.
She told the BBC: "Last year I was 24 miles in and not feeling great. It was quite hot and my heart was going extremely fast. I woke up on oxygen with a temperature of 106 degrees.
"It took me over six hours last time so if I don't shave a bit of time of my personal best then I'm giving up."
Rugby league stars Steve Prescott and Paul Sculthorpe are hoping to complete a gruelling eight day challenge by completing the marathon today.
Prescott, 38, was diagnosed with a rare form of stomach cancer in 2006 and is aiming to raise £16,000 for his charitable foundation.
The former St Helens players have already completed the Paris marathon, cycled 184 miles through France, and kayaked across the English Channel.
The pair then pedalled another 82 miles before setting off for the marathon.
It should also be the perfect temperature for participants, with highs of around 13C expected.
The London Marathon always attracts a number of famous faces on the start line, and shadow chancellor Ed Balls has said he is just hoping to get round the course.
The Morley and Outwood MP is running the marathon for the charities Action for Stammering Children and Whizz Kids, which provides equipment to help disabled youngsters live full lives.
A soldier who was blinded by an explosion in Afghanistan will run alongside an actor from Downton Abbey.
Lance Bombardier Rob Long said he would require "extreme concentration" to complete the course.
He is part of a three-man team that includes Lachlan Nieboer who played a blinded soldier in the latest series of the hit ITV drama.
L/Bdr Long, from Greenwich, said the only part of the route that he will be able to "see" is what his feet can feel.
"Extreme concentration is the main thing. I can only see exactly what is underneath my feet.
"It takes a lot of concentration to keep the rhythm and pace going. I've built up a lot of trust with my running partner," said the 24-year-old, who is running for Blind Veterans UK.
Meanwhile over 100 runners will try to break a series of bizarre marathon-related world records.
Sasha Kenney, 34, hopes to raise over £2,000 for the NSPCC as she bids to break the six-hour mark for quickest runner hula hooping.
"Someone said to me it couldn't be done," said Kenney, a fitness instructor from Wrexham, north Wales. "I see a lot of that in my profession so I want to prove them wrong."
George and Charley Phillips, from Hammersmith, west London, will attempt to beat a time of 8 hours and 25 minutes to become the fastest marathon runners on stilts.
The record for the tallest costume to complete a marathon could be broken by David Lawrenson, 39, from Lancashire, who is donning a 24ft version of the Blackpool Tower.