The head of the BBC has said the corporation needs to put "its house in order" after apologising to the Queen for a documentary blunder.
In a message to staff, director general Mark Thompson said nothing mattered more than honesty and accuracy.
The BBC could not allow even a small number of lapses to undermine its reputation, he said.
The BBC apologised for a promotional trailer which appeared to show the Queen storming out of a photo shoot.
Mr Thompson told staff: "We cannot allow even a small number of lapses, whether intentional or as a result of sloppiness, to undermine our reputation and the confidence of the public."
Earlier in the week, the BBC was fined £50,000 after the results of a Blue Peter competition were faked last November.
Mr Thompson said he will deliver a report to the BBC Trust next week before setting out how he intends to minimise the risk of anything like these "totally unacceptable incidents ever happening again".
The controller of BBC One, Peter Fincham, has said he was not planning to resign over the blunder.
He had told journalists at a media launch of the BBC One autumn schedule on Wednesday that the trailer for A Year With The Queen showed her "walking out in a huff" from a photo shoot.
He said showing the footage, which had misrepresented the sequence of events, was a regrettable "human error".