An Iraqi police chief cannot trust one third of his officers because they are loyal to illegal militias
General Abdul Hussein Al Saffe, head of policing in Dhi Qhar province, told the BBC's Paul Wood he could not sack them as they had political protection.
British commander Maj Gen Jonathan Shaw said Iraqi ministers knew the police were "not perfect".
But the Iraqis were making a judgement for "self-reliance", he said.
"There's always a balance when you have a newly created police force and army," he said.
"It's a question of balancing Iraqi enthusiasm for self-reliance with the risk of when the are capable of taking that responsibility, and that judgement really has to be made by Iraqis, which they are doing."
Another senior Iraqi officer, Brigadier General Ghalib al Jaza'aere, said he had been forced to hire 300-400 officers who were completely illiterate.
And he said one policeman had been sacked after he was caught smuggling weapons to be used against British troops, only to be later re-instated and promoted by officials in Baghdad.
He even said he feared some members of the police were using torture as they had done under Saddam Hussein.
Nearly 60% in Britain say invading Iraq was a mistake