For six years, The X Factor has been Saturday night TV's ratings powerhouse, courting controversy and criticism with each new series. Accusations of miming, unfair editing and shabby treatment meted out to hopefuls have all been lobbed at the programme.

So it is no surprise that after it launched its seventh series on Saturday night, ITV's karaoke-style contest finds itself embroiled in another row as hundreds of viewers took to social networking sites to accuse the programme's makers of "autotuning" the voices of contestants the judges favour to make them sound better than those set to be dropped.

Post-production technology had, the viewers claim, deprived the public of hearing the singing contest's competitors as nature intended.

The row follows the broadcasting of the audition rounds - the annual stomach-squirming spectacle where genuine talent shines through while the hopeless are encouraged to embarrass themselves before a baying live audience.

Amid cries of "cheat" and "shame", the programme stands charged with deceiving viewers, with many registering complaints on the official X Factor Facebook site and on Twitter.