Briton Duncan Scott has been sent a warning letter after becoming the latest to protest controversial Chinese swimmer Sun Yang’s presence at the world swimming titles in South Korea.

Not that he knew it on Wednesday.

Scott admitted he had no idea he had earned the ire of world body FINA after refusing to acknowledge the Chinese star’s controversial 200-metre freestyle win at Gwangju on Tuesday night.

Both Scott and Sun have been sent warnings by FINA for “inadequate behaviour” after the Chinese champion reacted angrily to the Briton’s snub.

Second-placed Sun was gifted the 200-metre world title after Lithuania’s Danas Rapsys was disqualification for a false start. Then co-bronze winner Scott followed the lead of Australia’s Mack Horton and refused to shake hands with Sun or take part in post-ceremony photos.

“You loser,” Sun told Scott as the athletes made their way off the podium.

“I’m winning, yes!”

Scott did not react during the tense confrontation.

Sun Yang to Duncan Scott: "You're a loser. I'm a winner." pic.twitter.com/W1AhD6XekV

— Nick Zaccardi (@nzaccardi) July 23, 2019

But he appeared unapologetic on Wednesday after finishing fifth in the 200-metre individual medley heats.

“I’ve got no clue. I’ve just literally swam. I don’t know as much as you guys right now,” he said of the FINA sanction.

Scott said earlier he had no regrets, saying he was with “Team Mack”.

“If [Sun] can’t respect our sport, then why should I respect him?” he said.

“Hopefully this will happen in more events.”

Olympic champion Horton lit the fuse for the world titles controversy when he refused to share a podium with Sun after the Chinese champion relegated him to 400-metre silver on Sunday night.

It prompted FINA to send warning letters to Horton and Swimming Australia.

Swimmers are livid that Sun has been allowed to compete in South Korea by FINA with a September Court of Arbitration for Sport hearing looming that may end the his career.

Sun has been accused of destroying vials of his blood with a hammer during a clash with testers last year.

Sun – who served a 2014 doping ban – faces a lifetime suspension if found guilty of the charges in September.

More drama looms at the world titles on Wednesday night, with triple Olympic champion Sun set to contest 800-metre freestyle final.

Australia’s Mitch Larkin paid tribute to Scott and Horton.

“They’re truly the most courageous guys and I couldn’t be prouder of both of them,” he said.

“They’re standing for what they believe in and that’s clean sport and if we didn’t believe that we wouldn’t be racing here today.”

World breaststroke champion Adam Peaty said he had a problem with Sun, who was booed when he sat on his lane rope and celebrated his surprise 200-metre win while a shattered Rapsys left the pool.

“If people are booing him, it’s for a reason,” Peaty said.

“He [Sun] should be asking himself now ‘should I really be in this sport when people are booing me?’

“If I was swimming [against Sun], I wouldn’t even get on the podium for that matter.”

Australian swimming legend Dawn Fraser joined in the growing condemnation of Sun on Wednesday, saying he should not be competing at the world championships and criticising his reaction to Scott’s podium protest.

“If I had been there, I would have kicked him in the backside,” the triple Olympic 100-metre freestyle champion said.

Fraser said she thought Sun should not be competing in South Korea.

“FINA should have stepped him down until that court case is over,” she said. “If he’s proven not guilty that’s fine, he can come back to swimming.

Scott’s manager, Rob Woodhouse, told Melbourne radio 3AW on Wednesday that Sun’s outburst was no surprise – and he was proud of the swimmer.

“Obviously Sun Yang was angry about Duncan’s stance but Duncan was very dignified in his process and how he went about it and just ignored Sun Yang’s antics,” he said.

“I am proud of him, and I believe most Britons are.”

-with AAP