Darius Danesh says Pop Idol was biased in favour of Gareth Gates over Will Young.
He claims the tracks Evergreen and Anything Is Possible were chosen to suit Gareth's voice.
Darius says Will even asked for them to be rearranged to give him a better chance.
He told The Sun: "We all recorded Evergreen and Anything Is Possible for the final. I did them too but they weren't even in my vocal range.
"They were written for Gareth's voice and Will was unhappy with that.
"Will asked Simon Cowell if he could have them rearranged into keys we could all sing and Simon just brushed him off.
"It was clear at the time Simon backed Gareth. He said it publicly afterwards and so I didn't find it surprising."