Lee Merrien was the first Briton home in the men's marathon in 30th place in two hours, 17 minutes on The Mall.
Uganda's Stephen Kiprotich stunned the Kenyan challenge to clinch a surprise Olympic gold medal.
The 23-year-old burst past Abel Kirui and Wilson Kipsang around the 38-kilometre mark to leave his two rivals trailing and claim only Uganda's second ever Olympic gold in athletics.
Kirui took the silver, 26 seconds adrift, and long-time leader Kipsang finished with the bronze.