Peter Davey, 32, of Llangefni, had been training for months before the gruelling race in which he joined 45,000 running through the streets of London.

His efforts were inspired by his 18-month-old son Tie who was born with the rare and painful condition severe recessive dystrophic epidermolysis bullosa (EB).

Describing the marathon, Peter said:"I carried on well until after the eleventh mile and then the rain and the cold that came with it started to get to my legs and the aches grew. I just about managed to grab a foil blanket from one of the many fantastic St Johns ambulance volunteers before he hail came down. As I approached Tower Bridge, the half way point, my legs were hurting the blisters were coming and after a couple of slips on the grids and manhole covers along the way I was doing more of a walk than a run. The next few miles blurred away as I tried to balance my intake of fluids and I have to say the sweets the kids were handing out kept all the tired marathon runners going - after 15 to16 hard miles there is nothing quite like a jelly baby to perk you up!

"After mile 19 I was encouraged that I had gone further than Jade Goody and kept up and going by positive thoughts. With approximately £5,000 riding on it there was no way I could quit.

"The crowds were cheering and the 600m to go sign came in to focus, something snapped in side and I threw the water bottle to the side of the road that I had been clutching over the previous 25miles - I no longer needed it and it was weighing me down. I started to pick up the pace and the blisters screamed at me, but the emotion behind the run also came to the surface and powered me on, but I held back the urge to run as I didn't know if i could carry on if I did and started passing everyone in a fast walk. As the 200m to go sign appeared I couldn't hold back any longer and ripped off the foil blanket and as the crowds cheered broke into a sprint for the finish. The crowds loved it and cheered me on. I was running on pure emotion and nothing else and as i crossed the finish line I knew I had done it.

"At the charity's after race party I was cheered in and hugged and told everybody that that was my last marathon!"

However, on the train home, Peter changed his mind and is now planning to run the Anglesey Marathon on September 21 for DeBRA, the society leading the research into Tie's condition.