* London is one of the "big five" in the elite marathon circuit, with New York, Boston, Berlin and Chicago.
* More than 382,000 people have completed the London race since it began in 1981.
* More than pound;80 million has been raised for charity over the years.
* You have to be 18 to enter; most entrants are aged between 30 and 39.
* Everyone has to pay pound;23.
* The oldest man to run last year was 90-year-old Alfred Gibson; the oldest woman was Jenny Wood Allen, 86.
* In 1997 Antonio Pinto of Portugal set a 2:07:55 course record for men: Ingrid Kristiansen of Norway set the 2:21:06 record for women in 1985.
* There will be 500 portable toilets for competitors en route.
* More than 6,000 race marshalls, 1,500 St John Ambulance personnel, 500 stretchers and 68 ambulances will be on hand.
* Twenty-three water stations will have more than 600,000 330ml bottles ready.
* A runner can lose up to two pints of water an hour through sweating.
* Runners will get through 40kg of petroleum jelly. This, says a spokeswoman for the marathon, "goes everywhere", between toes, inside legs, under bra straps.
* Five people have died running in the event's 19-year history.
* Most people finish within six hours, but marshalls can wait up to 10 hours for the stragglers.