Former England and Lions number eight Richards will return from a three-year worldwide coaching ban this summer when he starts work as Newcastle rugby director. He was suspended in 2009 during the fall-out from Harlequins' 6-5 Heineken Cup quarter-final defeat against Leinster at the Twickenham Stoop.
Richards, Quins rugby director at the time, instigated a chain of events that saw wing Tom Williams replaced by goalkicker and potential match-winner Nick Evans, who had earlier gone off injured.
Blood pouring from Williams' mouth, though, was fake and Richards paid a hefty price, subsequently resigning his position at Quins and then being banned.
"There is huge regret for everything that went on," 48-year-old Richards told the BBC.
"I felt very guilty. I put a lot of people in a position where they could have lost everything.
"I'm not the type of person to go match-fixing. I am very competitive, and the reason I did it is because I wanted to win a game. I shouldn't have done it."
Richards now hopes to put the whole unsavoury episode behind him, adding: "I hope I haven't served my three years for nothing. I hope other people have learned from my mistakes.
"I am still as competitive as ever, but I know the boundaries that I have to work in.
"People may think I am a cheat. That's up to them, if they want to. I have no issues if that's the way they feel.
"I know who I am, and I know what I did. I wasn't particularly pleased with myself. I wasn't proud of myself. But you move on and you look forward rather than back."