Mo Farah is facing criticism for abandoning yesterday's Birmingham Grand Prix and jetting back to the United States to seek answers from his coach Alberto Salazar over drug test allegations.
Farah announced his withdrawal from the Diamond League event on the morning of the competition, joining the likes of Jessica Ennis-Hill and Christine Ohuruogu on a lengthy list of pull-outs.
The 32-year-old had fronted up to the allegations over Salazar on Saturday, but later decided not to take part in the 1,500 metres, saying he was "physically and emotionally drained".
But Farah's domestic rival Andy Vernon, with whom he had been embroiled in a social media spat last year, suggested Farah would have been better off turning up to ease the disappointment of the fans.
Vernon said: "If it were me and I didn't want to race, I would come down and be at the track and say 'hi' to everyone. He's not going to get away with it, is he?
"I can't say it surprised me. When your head's not in it, it's very hard to go out there and do the job and not only that, he did a 10k race only last week.
"So to go out there and have the right head on your shoulders, to race would be very hard."
Farah is believed to have taken an early flight straight to Portland to see Salazar, who has been embroiled in allegations of doping.
There is no suggestion Farah has done anything wrong and both Salazar and another athlete implicated in the report, American Galen Rupp, have vigorously protested their innocence.
In a statement issued early yesterday morning, Farah said: "This week has been very stressful and taken a lot out of me.
"I have not been able to focus properly on the race and after the events of the last few days I feel emotionally and physically drained.
"I want to run well in the IAAF World Athletics Championships in Beijing and have decided it is better for me to go back to the US, seek answers to my questions and get back into training.
"I apologise to the people who bought tickets to come and watch me race and ask for your understanding at this time."
The 32-year-old refused to bow to pressure to end his relationship with Salazar and expressed his anger at being implicated in the allegations.
Farah said: "I'm not leaving Alberto, for the reason I've not seen any clear evidence. I'm really angry at this situation. It's not fair, it's not right. I haven't done anything but my name's getting dragged through the mud."
Meanwhile, Adam Gemili ran his first ever sub-10 seconds 100m but then immediately crashed to the ground with a torn hamstring.
The 21-year-old ran 9.97 seconds in Birmingham to become the first Briton to go under both 10 seconds in the 100m and 20 seconds in the 200m.
He clutched his leg a stride after crossing the line in second place and was taken from the track in a wheelchair.
Dina Asher-Smith, 19, ran the second quickest 200m by a British woman. She finished third in a personal best 22.30 second.
The British 100m record holder was just a hundredth of a second adrift of winner Jeneba Tarmoh and Allyson Felix in second, who both clocked 22.29 seconds.
Elsewhere, Olympic champion Greg Rutherford won the men's long jump by equalling his second longest jump ever, a season's best 8.35m leap.