It was a remarkable display of defiance, just six days after bombs exploded at the end of the Boston Marathon.
Among the throng were a few familiar faces, as the usual crop of celebrities took on the 26.2-mile course.
Charity was the name of the game for these renowned runners, but we at World of Sport can't help injecting an element of competition into things.
So here is our league table of celebrity marathon runners - you might find a surprising name at the bottom!
2013 LONDON MARATHON - CELEBRITY RUNNERS
1-Christian Dailly - Ex-Scotland footballer - 3:06:26
2-Harry Judd - McFly drummer, Strictly Come Dancing winner - 3:31:15
3-Andrew Strauss - Ex-England cricket captain - 3:31:52
4-Sophie Raworth - BBC newsreader - 3:44:19
5-Phil Clarke - Rugby league legend - 3:56:51
6-Nikki Sanderson - Coronation Street actress - 4:02:30
7-Michel Roux - Chef - 4:07:40
8-Nick Pickard - Holloyoaks actor - 4:17:00
9-Terry O'Connor - Rugby league legend - 4:20:11
10-Sian Williams - BBC newsreader - 4:26:45
11-Kelly Sotherton - Olympic medal-winning heptathlete - 4:28:52
12-Iwan Thomas - Olympic medal-winning 400m runner - 4:36:54
13-Susanna Reid - BBC newsreader - 4:43:19
14-Amanda Mealing - Holby City actress - 4:57:09
15-Mike Bushell - BBC newsreader - 5:10:29
16-Ed Balls - Shadow Chancellor - 5:14:13
17-Katherine Jenkins - Classical singer - 5:26:42
18-Amy Childs - TOWIE reality star - 5:47:12
19-Cheryl Baker - Ex-Bucks Fizz and Record Breakers - 6:17:06
20-Jonathan Pearce - Football commentator - 6:39:14
21-Sophie Anderton - Model - 6:52:39
22-Mo Farah - Double Olympic gold medallist - DID NOT FINISH