Scott Overall admitted he misjudged the scorching conditions in the Olympic marathon on Sunday.
The 29-year-old former shoe salesman, who made his name by finishing fifth at the Berlin marathon last September to book his place at London 2012, came home in 61st place. Eighty-five athletes finished the race.
Overall appeared to cope with the 25 degree heat and blazing sun in the first half of the race, passing the midway point in 29th place. He climbed two more places before fading after the 30-kilometre mark to come home in two hours 22.37 minutes.
"It was tough," said Overall, whose team-mate Lee Merrien finished 30th in two hrs 17.00 mins. "I wanted to come through (halfway) in 65 or 66 minutes. I came through in 65.30 mins, but even before halfway I was feeling like that was probably a little bit quick.
"I probably didn't respect the conditions enough. I think I really suffered there on the last lap."
Uganda's Stephen Kiprotich took the gold medal, bursting past Kenyan duo Abel Kirui and Wilson Kipsang around the 38km mark to leave his two rivals trailing and claim only his country's second ever Olympic gold in athletics and their first in 40 years. In front of packed crowds rows deep all along the looped central London course, he came home in 2:08.01.
Overall added: "I said before the race it's going to be tough to hold back when the crowd were so loud and were there shouting and cheering for the British guys. Obviously in hindsight I should have gone out slower.
"Those guys who did that, including Lee, went through slower at halfway then were stronger on the last lap. Everyone suffered on the third lap, even the leaders."
Merrien said: "My target was top 20, maybe just inside if I had had an absolute stormer. But looking at that field, it was very strong. I think on paper there were probably a good 60 or 70 people at least faster than me so I can't be disappointed with that."