Kristian Gkolomeev bags $1m bonus for smashing 50m freestyle world record at Enhanced Games

Gkolomeev, who failed to make the podium in four Olympics, won the same bonus last February when he swam 20.89 ​to beat Brazilian Cesar Cielo's previous world record of 20.91 set in 2009.

But participants, lured by prize money of up to $1 million for beating world records, will include Olympic medallist swimmers James Magnussen, Cody Miller and Ben Proud, who have all taken drugs.

Records set at the divisive competition are not considered official because athletes are allowed to take performance-enhancing drugs.

But by the end of the inaugural Enhanced Games in Las Vegas organisers were left with one abiding emotion.