Former marathon world record holder Haile Gebrselassie has accepted defeat in his bid to represent his country in London 2012.

The Ethiopian has seen eighteen compatriots clock faster marathon times this year and could only manage a fourth-place finish in February’s Tokyo Marathon with a time of 2:08.17.

The two-time 10,000m Olympic gold medallist, a man who overcame Olympic odds and at one point was one of the sure-fire Olympic bets, can no longer compete with the younger Ethiopian athletes, according to his manager Jos Hermans.

"Many Ethiopian athletes run 2:04 and Haile cannot run that any more. He has given up on the Olympics with pain in his heart," said Hermans.

Despite the disappointment, Gebrselassie will defend his 10k Great Manchester Run title next month. The 39-year-old has won the event in each of the last three years.

"Although I will not be taking part in the Olympic marathon I am still enjoying my athletics career and looking forward to coming to Manchester again and to a course which I love," he said.

Gebrselassie, winner of four World 10,000m titles, will call it a day after racing in the middle distance event in Holland next month.

Gebrselassie was desperate to retire after the summer Games, but accepted it was the right time to give up on his dream and bow out of competitive track racing.

"This will be my last 10,000 metres race. But I still feel good. There is only a small difference compared to 2011. I am just a bit slower now," he added.

The veteran athlete showed his class in last weekend’s "Emperor versus the Queen" race in Vienna. Gebrselassie beat Britain’s Paula Radcliffe in the 13.1 mile race despite giving up a head start of seven minutes 52 seconds.

Instead of being a warm-up ahead of London 2012, it was one of the final glimpses of a glittering 20-year career.