Armed Force Minister Adam Ingram has said if pictures of British soldiers torturing an Iraqi prisoner are genuine then they are “appalling”.
Military police had to be given time to investigate photos which appear to show a soldier using violence and urinating on a captive, he told the BBC.
“Such wrongdoing if proven besmirches the good name of the… armed forces. We will not tolerate that,” he said.
The photographs in the Daily Mirror have also been condemned by Number 10.
Earlier pictures showing American troops humiliating Iraqi prisoners, with a hooded and naked prisoner standing on a box with wires attached to his genitals, also generated outrage.
US President George W Bush vowed that those responsible would be “taken care of”.
Mr Ingram said there was no “culture of abuse” in the British Army despite the fact that five separate inquiries into maltreatment are under way.
He admitted: “If these allegations are true, they are appalling, they are despicable and there can be no justification for them at all.”
And he said the Royal Military Police’s “full intensity” inquiry would “not leave any stone unturned” in the investigation into the latest photos.
Those who are opposed to the coalition’s occupation of Iraq would employ “full exploitation of these incidents”, Mr Ingram said.
A Downing Street spokesman said: “We expect the highest standards of conduct from our forces in Iraq despite the difficulties they face.”
The Mirror says the pictures were handed over by British soldiers who claimed a rogue element in the British army was responsible for abusing prisoners and civilians.
Speaking on condition of anonymity, the soldiers told the paper no charges were brought against the unnamed captive.
They allege that during his eight-hour ordeal he was threatened with execution, his jaw broken and his teeth smashed.
After being beaten and urinated on, he was driven away and dumped from the back of a moving vehicle, the soldiers claimed, unaware if he was dead.
The reason for making the photos public was, they said, to show why the US-UK coalition was encountering such fierce resistance in Iraq.
One told the paper: “We are not helping ourselves out there. We are never going to get them on our side. We are fighting a losing war.”
In a press conference, Sir Mike Jackson, Chief of General Staff, said: “If proven, not only is such appalling conduct clearly unlawful but also contravenes the British Army’s high standards of conduct.
“The allegations are already under investigation.
“Again, if proven, the perpetrators are not fit to wear the Queen’s uniform and they have besmirched the Army’s good name and conduct.”
But he said the Army should not be judged on the behaviour of a few soldiers who had let down the good work of tens of thousands of others.
Ahmed al-Sheik, editor-in-chief of Arab TV news channel, said the photographs would outrage Arabs around the world.
“These scenes are humiliating not only to the Iraqis, but to every Arab citizen around the world,” he told BBC Two’s Newsnight.
Meanwhile former foreign secretary Lord Hurd said the situation in Iraq was in danger of spiralling out of control.
“In Iraq we’re in a nosedive. Things are happening which were entirely predictable and predicted.
“An army of liberation, particularly a British/American one, turns within hours into an army of occupation.”