C4 admitted on Thursday that the premium phone line con had occurred on at least two series of daytime chat show Richard & Judy.
They also said they would repay all £1 callers, which may cost them £700,000.
Co-host Richard Maddeley was furious about the scam, which affected the show’s popular phone-in competition, You Say We Pay.
“The word ‘****ing’ isn’t permissible on TV, but I feel ****ing furious about this and so does Judy. We’re livid about it,” he told the Mirror.
“I think it’s a cock-up, not a conspiracy. But we’ll wait and see what the inquiry turns up. We’re angry on behalf of our viewers.”
On Wednesday it was reported that a contest winner Lilly Cooper was told early in a 2002 programme that she had been chosen as the day’s competitor, but Richard & Judy continued to urge people to ring in and enter.
But C4 only admitted that the con affected the last two series, comprising 70 episodes. That meant £700,000 had been erroneously collected by the show’s producers.