Before the main action gets underway, 39 club runners test the London 2012 Olympic marathon route at a 3:00 pace.
And they're off!
London 2012 chairman Sebastian Coe keeps an eye on the test event
Harrow runner Chris Finill finishes first - an honour bestowed upon him for competing all 31 London Marathons
Then the pack follows...
That's a scoreboard we wouldn't mind seeing for the actual London 2012 Marathon.
Later in the day, the women's elites line up to take the Bupa London 10000 title. The pressure was on road 10K world record holder Paula Radcliffe who was competing for the first time in 18 months.
Men's Mo Farah favourite prepares to defend his title
Jo Pavey pulled away in the closing stages of the race to take the title in 32:22
Taking second place was Gemma Steel finishing with a PB of 32:48
Paula Radcliffe visibly struggled on the course and finished third in 33:17. Afterwards she revealed she has a torn disc in her back and branded the race a 'disaster'.
Middle -distance star Mo Farah produces yet another comfortable win in 29:15
Two very worthy Brit winners celebrate victory in the capital
Then it's time for thousands of runners to race around some of London's finest sights. The queue at the Bupa Boost Zone grows as finishers return with their medals.