A Scotland Yard computer error has led to police constables being promoted to sergeant even though they failed their exams.
The incident occurred after a computer database hitch meant that police officers who did not make the grade with their sergeant assessments were told they had passed and officers who gained flying colours were told they had failed.
The results were sent out before the error was identified and, rather than tell jubilant candidates that they had failed, Yard chiefs decided to promote everyone effected.
Robin Merrett, staff officer to the director of personnel, said the problem occurred when two databases were being merged and 110 candidates' entries were corrupted.
Each officer had a candidate number guaranteeing their anonymity to the people marking the exam. But when the candidate numbers were linked back to the database containing the corresponding names corruption occurred.
Merrett said it was decided that it would be "unfair and inappropriate" to go back on the initial results.
"A full investigation is now taking place to try to work out what went wrong. Doubtless there will be a detailed review on the quality assurances of the system and we will make sure this never happens again," he said.