The London Marathon was first run on March 29, 1981 and has been held in the spring of every year since 2010. It is sponsored by Virgin Money and was founded by the former Olympic champion and journalist Chris Brasher and Welsh athlete John Disley. It is organized by Hugh Brasher (son of Chris) as Race Director and Nick Bitel as Chief Executive. Set over a largely flat course around the River Thames, the race begins at three separate points around Blackheath and finishes in The Mall alongside St. James's Park.

Since the first marathon, the course has undergone very few route changes. In 1982, the finishing post was moved from Constitution Hill to Westminster Bridge due to construction works. It remained there for twelve years before moving to its present location at The Mall.