Mo Farah runs half of London Marathon, ahead of full 2014 race

Great Britain's double Olympic champion Mo Farah withdrew from the London Marathon as planned just under halfway through the 26.2-mile course.

The 30-year-old used this year's race as part of his preparations to compete over the full distance in 2014.

"Next year I'll come and do the full marathon," he told BBC Sport.

"I've learned the biggest lesson of my life. If I had come here next year and made a mess of the race I don't think I could have dealt with that."

Farah became only the seventh man to win both the 5,000m and 10,000m at a single Olympics in the 2012 London Games.

In October, his coach Alberto Salazar hinted that Farah may look to run the marathon at Rio 2016.

"This year I'll be concentrating on the track. It's hard to do marathon and track racing," added Farah.

"The biggest challenge I had was picking up the right drink and I made a mess of that. I'll watch the race back to see how much of a mess I made of it."

Before the race, which was won by Ethiopia's Tsegaye Kebede, Farah said to BBC Radio 5 live that he had overslept, but later revealed on Twitter that his comments were "just a joke".

Farah, who lives and trains in the United States, announced his intention to run half of this year's race in February.

His plan was questioned by women's marathon world record holder Paula Radcliffe, while Farah's reported fee of £450,000 for the two appearances was also highlighted in some sections of the media.

Speaking on Friday, Farah said: "I'm not here to just turn out for a bit of money.

"That's one of the things that hurts. It's not nice but all the people who know me know I'm not the sort of person who would do that. I genuinely enjoy my athletics.

"I'm here to learn about the course, so that next year I'm ready to go. It's a no-brainer when you think about it."