The British singer, Ricky Wilson suffered a blackout just over two miles (three kilometres) from the finish line and was forced to pull out after he was treated by paramedics.
Ricky Wilson has now spoken of his disappointment after failing to complete the 26.4 mile (42.2 kilometre) trek and has promised to hit the streets later this week to finish where he left off.
In a series of posts on his Twitter.com page, he writes, "I collapsed after three hours 20 at Mile 24 of the Marathon. Very disappointed! Will try and get it finished before the weekend... Also, thanks a lot to all the ambulance guys who brought me round. I can't remember their names but I couldn't recall mine at the time... The doctors asked me loads of questions as I recovered to see how my head was doing. I'm still struggling with the Prime Minister one."