Tola Shura Kitata of Ethiopia was second, followed by Mo Farah, who set a British record 2:06:21 in front of his home fans who lined the streets in temperatures that reached 73.8 degrees (23.2 Celsius) near the finish.
Having taken a break from the London Marathon previous year to try to run a sub-two-hour marathon in Italy, Kipchoge returned to add to his 2015 and 2016 titles easily, finishing ahead of Ethiopias Tola Shura Kitata in 2:04:27, two-and-a-half minutes off Dennis Kimmettos world record. A year ago I couldn't really celebrate winning because of the state of mind I was in, I just feel a lot clearer minded now and I just love this race.
The April heatwave could see the mercury on Sunday soar higher than the 22.2C recorded in 1996 and 2007, with organisers urging participants to "adjust their goals and run at a slower pace".
Great Britain's Jade Jones-Hall, after her Commonwealth Games triathlon gold and marathon bronze, finished seventh in a time 1.50.04, her quickest time on the London course. It's weird that my endurance pace has got a lot better as I've got older. Cheruiyot completed the 26.2-mile (42.2-kilometer) course in front of Buckingham Palace in 2 hours, 18 minutes, 30 seconds. Tadelech Bekele of Ethiopia was third.
Last year, Keitany broke Radcliffe's world record without male pacers by 41 seconds, winning her third London title in 2:17:01.
Cheruiyot, who won her first marathon in Frankfurt only last October, came out of nowhere to race past Keitany, who struggled over the finish line fifth and remains stuck on three wins in the English capital, one behind Norwegian Ingrid Kristiansen's career total.
The mass race will begin when Queen Elizabeth steps onto a special podium in front of the Round Tower in the grounds of Windsor Castle to push the start button at 10.00 a.m.
Madison de Rozario of Australia won the women's wheelchair race for the first time ahead of four-time champion Tatyana McFadden, whose fellow American, Susannah Scaroni, was third.
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