The TV phone-in scandal has been ‘a wake-up call’ for the industry, BBC director-general Mark Thompson said.

And he acknowledged that the corporation needed to rebuild trust with viewers, adding that Blue Peter and Saturday Kitchen programme makers had made serious errors of judgment.

But the BBC boss insisted there was no intent to deliberately mislead the public or gain financially.

He said they was investigating the fiasco, but wouldn’t comment on whether sackings could follow.

Blue Peter apologised last week after arranging for a studio visitor to win a charity phone-in competition after a technical glitch meant that children calling in could not get through.

Premium rate phone line regulator Icstis is investigating, and media watchdog Ofcom has asked the BBC for further information.

The BBC previously admitted its Saturday Kitchen programme had asked viewers to phone a pre-recorded show.

A third BBC show, the children’s programme Smile, has been accused of misleading viewers by asking them to phone in to take part in an apparently live game when it was pre-recorded.

The row first blew up on Channel 4’s Richard & Judy, when it emerged viewers were encouraged to phone the show’s premium rate number after the potential winners had been chosen.