The 38-year-old Briton, who had fallen 22 seconds short of that target while hampered by an ankle problem at the European 10,000m Cup in Birmingham on June 5, was marginally faster in a specially arranged race at the British Athletics Championships.

But a time of 27:47.04 on an unhelpfully windy night still left him significantly short of what he required.

Sir Mo, who has also won two Olympic 5,000 metres titles and six world titles over 5,000 and 10,000m, had returned to the track after spending more than three years concentrating on road running after deciding to have one last go at the Olympics.

He was on target pace through halfway but by the 6,000m mark he was on his own and, despite the encouragement of the crowd, began to drop off the pace.

With 2,000m remaining he was 10 seconds adrift and he lost more time, grimacing over the final lap.

It was a hugely anticlimactic ending to Sir Mo's intended Olympic campaign at a British Trials weekend that is not even being shown on terrestrial television.

"Thank you for everyone who's come out," Farah said in a trackside interview.

"Oh my goodness.

"I don't know what to say.

"You go out there and give it your all.

"I've been lucky enough to have had the long career I've had.

"I'm very grateful but that's all I had today."

Asked if tonight marked the end of his track career, Farah said: "It's a tough one.

"If I can't compete with the best I'm not just going there to finish in a final.

"Tonight shows it's not good enough."