I don't wish to trigger anybody, but when threads such as 'clean WRs' come up, most people pick Nick Willis and his 3:29.66, set three years ago today in Monaco, as the 1500 clean WR.
Seems Nick agrees as he recently posted on Instagram that he was looking forward to testing his form against his American and European rivals (no mention of Kenyans).
Don't blame him, the guy was cheated out of Olympic gold by Kiprop and the corrupt Kenyan anti-doping system.
Only 1/100th of a second faster than Steve Cram's previous WR in 1985.
Some say Willis set his best times at Monaco, but you have to consider also that he was competing for a decade against cheats, including full throttle EPO users. Since Kiprop's bust he has related how hard it was to stay motivated when he suspected others of being rocket fuelled. How much faster could he have gone if he had been competing on a level playing field, with the glory of being recognized as the best in the world? I'm pretty sure that Cram, for example, would have given up athletics in his teens if he had been born 10 years later into the EPO era.
As for how long it will last, I don't see Willis or anybody breaking it tomorrow, or for that matter for another couple of years when Jakob will surely be going sub 3:30. Down the line, if they keep progressing, Kane Elliott and Max Burgin have a chance too.