Jon was raising money for The Neuroblastoma Society.
Jon said on his Just Giving webpage ...he has raised £2,156.40 (You can still give).
"I ran 3 marathons when I was a student and they hurt a lot. In fact it was enough to put me off running more than 10km on the road for good. But I thought this was a good cause, as one of my brothers best friends lost his only child to neuroblastoma.
In order to raise as much as I can, I am running as Fred Flintstone in the London Marathon. I have also registered with Guinness to attempt to break the World Record for the fastest cartoon character. My fastest marathon was 3.20 so the existing record was looking potentially achievable at 3.08. Or so I thought, until Guinness corrected me - the World Record for the fastest cartoon character, set in Oct 2010 in Abingdon, is now 2.48."
You did it Jon. Congratulations.
Jon, 43, who lives in Sheffield and works as a doctor placed 359th overall, 68th in his age category
Here are Jon's results
Earlier this year, on New Years day, Jon did his first Bob Graham Round with his friend Steve Watts in a time of 23.20 - they lost 20 minutes cutting steps on Lords Rake.
You can read about Jon's Winter Bob Graham round at www.runfurther.com
Jon is competing in the The North Face® Ultra-Trail du Mont-Blanc in August and is also a gear reviewer for UKClimbing.com (Kahtoola Microspikes Review).
We hope to have photos of Jon in his Fred Flintstone costume later.
Congratulations to any other climbers who ran the London Marathon today.