The British Broadcasting Corp. said Wednesday it was suspending all phone-in contests and interactive quizzes after an investigation exposed several incidents in which competition winners were faked.

The BBC, which has been battered by revelations about rigged contests and doctored footage, said an internal inquiry had found that "a small number of production staff ... have passed themselves off as viewers and listeners."

BBC Director-General Mark Thompson said seven such cases had been found.

"We must now swiftly put our house in order," he said.

Thompson said phone-in contests on radio and TV would cease from midnight Wednesday and Internet competitions would be taken down as soon as possible.

The BBC said a review of about 1 million hours of output had found that several high-profile shows, including the Children In Need and Comic Relief charity telethons, had used fictitious contest winners or members of staff posing as viewers and listeners.

The broadcaster said it would also hold an independent inquiry into how clips from a documentary were assembled so they appeared to show Queen Elizabeth II storming out of a photo shoot. It turned out the order of the footage had been reversed.

The BBC's governing Trust said it was "deeply concerned that significant failures of control and compliance within the BBC, and in some cases by its suppliers, have compromised the BBC's values of accuracy and honesty."

Earlier this month, the BBC was fined $100,000 by regulators for using a studio guest to pose as the winner of a phone-in on the children's program "Blue Peter."

Private broadcasters have also been exposed for rigging phone-in competitions. Eckoh UK Ltd., which runs contests for Channel 4's "Richard and Judy" talk show, was fined $308,000 earlier this month for encouraging viewers to call a premium-rate number even after a winner had been selected.

But the publicly funded BBC, which prides itself on its authority and impartiality, has the most to lose.

Thompson said 16,500 staff working on BBC programs would be sent to a course entitled "Safeguarding Trust."

"Nothing matters more than trust and fair dealing with our audiences," he said.

"It is right that we are open with the public when we have fallen short and that we demonstrate that we take this very seriously indeed."

Last week, the BBC apologized to the queen for wrongly implying she had walked out of a portrait sitting with photographer Annie Leibovitz. The BBC said a trailer for an upcoming documentary, screened for the press, showed the queen arriving at -- not departing -- the sitting.

The BBC said production company RDF Media had made the faulty footage several months ago and that it was never intended to be seen by the public or the media.