'A lot': Mack Horton's explosive claims about doping in swimming

Australian swimmer Mack Horton says he still would have staged his anti-doping protest at the world titles in South Korea if he had of known about teammate Shayna Jack's positive test.

Horton refused to share the podium with Chinese rival Sun Yang, who served a 2014 doping ban, after the triple Olympic champion was allowed to compete ahead of a hearing in September that may end his career.

Unbeknown to Horton, Jack had been sent home from the world titles team training camp after testing positive for Ligandrol, a non-steroid anabolic agent popular with bodybuilders.

"Nothing changes," Horton told Channel Seven's Sunday Night program when asked if he would have gone ahead with his protest if he had known.

"We are not hypocrites as long as we are enforcing what we are standing for and I think Australia is definitely standing for clean sport.

"As soon as she returns a positive sample, she's returned to Australia, she's not competing at a world championships.

"That gives me faith in the Australian system and that Australians demand clean sport and we won't let our own athletes get away with it. We can question and demand more from the world.

“We don’t know how many athletes, how many swimmers are clean ... but a lot (aren’t).”

Horton had second thoughts

Horton revealed he had been thinking about staging a protest in the days before the event but had some second thoughts after coming second in the 400m final.

As he walked to the podium for the presentation, he asked Italian swimmer Gabrielle Detti, who placed third, to join him in protest.

"He said 'no, no, I don't want to do that,' which is fair enough, I respect that," Horton said.

"I wasn't sure if I was going to do it but I did it at the last minute because I didn't want to live with the regret thinking back maybe I should have done that at that moment.

"Standing there, it was tense, it was awkward. No one really knew what to do and then all of a sudden the crowd realised what was going on and started applauding and I guess filled me with emotion and I was like 'OK, this was the right thing to do'."

He said he had received support from teammates, sponsors and fellow athletes for his stance and was relieved when Scotland's Duncan Scott staged a second protest against Yang two nights later.

"It was kind of like 'hey, other people are thinking the same way that you're thinking, other people believe in what you're doing'. It was just a kind of pat on the back of support," Horton said.

"I'd rather just get in the pool and swim my race and not have to worry about all this stuff but when nobody's doing anything, the athletes have to take over.