Greg Billingham finished in just over seven days
Greg Billingham, from Poynton in Cheshire, completed the 26.2 mile (42.16km) course in slow motion and finished at lunchtime on Sunday.
The builder, who was raising money for Children with Leukaemia, "ran" one step every five to six seconds, after setting off with 36,000 other runners.He said he had practised for weeks at the building site where he works.
Martin Lel, the winner in 2005, out-sprinted his rivals to claim his second victory in the marathon.
The Kenyan won in a time of two hours, seven minutes and 41 seconds.