On Tuesday it was confirmed the former world champion has been banned from sport for two years for a failed anti-doping test following his fight with Brook last February.

In an independent hearing, the charges against him were proven, but the panel ruled out deliberate or reckless conduct by Khan and also found that the ostarine in his system was too low to enhance his performance - and would have needed to be a thousand times stronger to have an impact.

• Amir Khan handed two-year ban from all sport
• Amir Khan's first words after ban: I've never cheated
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When asked by Sky Sports how the substance got into his system, he said: "I have no idea. It could be meeting people, shaking people's hands. The amount of ostarine in my blood was 0.5, which is say [in] an Olympic size swimming pool, it's smaller than a grain of salt.

"I don't know how it got into my system, maybe shaking hands, maybe sharing a drink with somebody."

He added: "The results say it could not have changed my performance and with the amount that was in my blood it could not have made me any stronger or better. It was such a tiny amount which somehow got into the system."

Khan lost the fight via sixth-round stoppage and announced his retirement from the sport a few weeks later, but does not want Tuesday's revelations to tarnish his whole career.

"I don't want to be remembered for something like this, that'll hurt me a lot," he added.

"If people remember me for just this incident that's happened then I think it'll always upset me because I know it was never done on purpose.

"Hopefully people believe me and maybe take more precaution, especially the young and upcoming fighters can learn from me how mistakes can happen."

The amount of ostarine found in his urine sample was half a nanogram per milliletre with a nanogram being the equivalent of one billionth of a gram.

Despite the quantities involved, Khan says he is willing to bear some responsibility for the findings.

"I'm very sorry. I have to take some sort of responsibility," he said.

"At the end of the day, it's been found in my system but I can honestly say to the public and to everyone out there, it's something I'd never ever do.

"It's such a tiny amount that was never of any benefit at all. I don't know how it got in there but I should've maybe taken a little bit more precaution. I'm very sorry about it."

'It was a big shock to me'

The news of the two-year ban was announced on Tuesday morning shortly after Khan had appeared on breakfast television to discuss being robbed at gunpoint.

And Khan said the timing of the positive test was also a surprise as it came many weeks after his defeat to Brook.

"I never took anything that was illegal. Obviously I have a big team around me to make sure I'm taking the right supplements and the right things, so when it first came out that I was positive it was a shock to me, my team and everybody.

"I was tested throughout the whole training camp. This positive result came out literally weeks after the fight which normally you'd think it'd be a week. Because it was weeks after the fight it was hard for me to then think what did I do wrong? Was there something I took so I could then pick up on?

"It was a big shock to me."

Khan unified world titles at super-lightweight and faced pound-for-pound stars Saul 'Canelo' Alvarez and Terence Crawford during a 40-fight career featuring 34 wins and six defeats.

He also lost a close world super-lightweight title fight to Lamont Petersen via split decision in 2011, with the American fighter later being stripped of his WBA belt after a failed drug test.

"I can honestly say that I've always been a clean fighter. I've always been the type of person who's always asked to be drug tested," he said.

"I've always wanted, [with] every fight that I've been in, to put the random drugs testing in there. I've always had people like WADA, USADA and UK anti-doping on board.

"I've been in a position where I've boxed a guy [Peterson] before who has been on these substances and you could see how upset I was after that fight, after I knew that he was on something, so I'm totally against stuff like this."

Khan also said he will contact Brook to explain the situation in person. "I don't want him thinking that I've just forgotten about him," he said. "I was fighting Kell Brook and either of us could've got hurt in that ring so I think it takes a man to give him a call and say, 'This was found in my system'.

"Kell, I just want to say it was nothing like that and hopefully we can clear it from there."

Brook: I could be in a wheelchair... this will tarnish Amir's legacy

Brook has responded in an interview with iFL TV and demanded action against Khan. He said: "It could be a completely different story. I could be in a wheelchair now, with him seriously destroying my life or killing me, making me crippled forever.

"Because I won, people are gonna forget about it. He came into that ring cheating, trying to boost himself up, trying to get the advantage on me - instead of doing it in a 12-week camp naturally. He's taken drugs to enhance his performance, so he can seriously hurt me in that ring, [which] you can legally get killed in. He needs to pay bad.

"As much as this is bad publicity for him, he needs to pay financially, he needs to pay to let everyone out there know that you can't fight and just retire if you get caught and get no punishment.

"He's gonna have to live with that. People are gonna think: 'How long's he been on these drugs?' Of course it's gonna tarnish his career terribly. He's gone in there, got an absolute pasting, hammering. He's got to live with that beating for the rest of his life, he's got to live with cheating."