Broadcast watchdog Ofcom has fined the BBC £50,000 for faking the results of a phone-in on children's show Blue Peter last year.
The fine is the first ever financial penalty imposed on the BBC by Ofcom and comes after the organisation earlier apologised "unequivocally" for the incident.
All but £5,000 of the fine was levied against breaches of the rules that "competitions should be conducted fairly" and that "due care must be taken over the physical and emotional welfare and the dignity of people under 18".
The remainder was imposed for a secondary offence keeping the lines open and displaying the telephone number despite showing a caption saying that lines had been closed.
In the November 17th episode of the show producers asked a child visiting the studio to pretend to be a caller, rather than selecting a caller to give their answer live on air.
The watchdog's adjudication stated: "Ofcom viewed the breaches of the code in relation to the original broadcast on BBC1 as particularly serious. It was of great concern that, whatever the motivation, the decision to put to air a fake winner resulted in a child audience being misled."
It rejected the BBC's assertion that the incident had been a "serious error of misjudgement" or an accident because the breaches had occurred "as a result of a decision that was planned in advance of the programmes broadcast - albeit only shortly before it".
The BBC had argued that the actions of a pressured junior researcher could not be taken to reflect those of the institution as a whole.
But Ofcom's adjudication stated: "The committee did not consider that the breaches occurred as a result of the actions of one researcher. In any event, the BBC must take full responsibility for the action of its staff."
Responding to today's announcement, the BBC said: "As our previous statements have made clear, we fully accept the seriousness of this case and apologise for the breach of trust with our audiences.
"We regret that Ofcom found it necessary to impose a fine on the BBC. However we are pleased Ofcom's finding accepts that Blue Peter always intended to conduct a 'genuine competition' and recognises the BBC's good compliance record."
Last week premium rate telephone services regulator Icstis fined the company behind Channel 4's Richard and Judy show £150,000 for misleading its audience about its You Say We Pay quiz.