Olympics Rio 2016: Phelps accused of hypocrisy after selfie with Gatlin

Phelps had praised his team-mate Lilly King for her vocal criticism of Yulia Efimova, and he said: "It's kind of sad that today in sports in general, not just in swimming, there are people who are testing positive and are allowed back in the sport, and multiple times."

King had also said that she did not think athletes who had been caught doping should be allowed to compete - a category that would include Gatlin, banned in 2006 for a positive drugs test.

Almost immediately afterwards, though, a photograph of a smiling Phelps posing for a selfie with Gatlin began to circulate.

The photo had initially been posted by Gatlin on Instagram over the first weekend of the Games.

Unsurprisingly, the response to that picture combined with Phelps's strong words was somewhat frosty.