Commonwealth marathon bronze medallist Dan Robinson has hit back at claims that British distance runners are not working hard enough to succeed.
Robinson is running in Sunday's London Marathon
London Marathon race director Dave Bedford questioned the commitment of the current crop of young British marathoners on Thursday.
Robinson told BBC Sport: "I agree that we're not running as fast as guys 20 or 30 years ago.
"But I really do not think laziness is to blame."
Robinson said the British male distance runners were "incredibly committed and motivated", adding that he trained "twice a day, very hard".
But he conceded: "You can say that the talent isn't there, or that we don't race each other enough, or we don't train smart - but motivation from the guys that are doing it is as high as it's ever been."
Bedford had told BBC Sport: "The one thing you can't buy is athletes with the right commitment.
"They've got to feel that themselves, and at the moment they don't.
"We used to train three times a day, 200 miles a week, and it's very clear that if you have that sort of commitment, you will run very fast.
"But you have to be prepared to commit. You can't be out nightclubbing or messing around with PlayStations."
Robinson, who came 12th at the World Championships last summer, said: "He's right that you can't argue with the times.
"Until we're running two hours nine minutes or 2:08, to some extent I agree with him. I respect Dave enormously. But the athletes I know just aren't lazy.
"I don't think I've been to a nightclub for about six years, and I don't know any of the guys running 2:20 or better that do.
"Why would we want to go to nightclubs? I think that's totally irrelevant.
"It's easy to say, 'you don't train hard enough - train harder and you'll run faster'. But we all do everything we can to get faster. If I ran 200 miles a week, I'd struggle to walk."
With the withdrawal through injury of 34-year-old Jon Brown, it is unlikely that a British man will finish in the top 10 in Sunday's London Marathon.
British men won six of the first 13 London Marathons, but have not claimed any of the last 12 titles.
The British men's record for the marathon has stood for 21 years, and four of the five fastest British male times in history were recorded over 20 years ago.