Today's front pages are dominated by the gruesome beheading of an American civilian in Iraq.

Nick Berg's murder was videotaped and posted online by a group linked to al Qaeda in revenge for the torture of Iraqis by American prison guards.

The video was made public hours after Jack Straw strongly condemned the abuse by American troops.

The foreign secretary told the Commons: "The situation in Iraq is overshadowed by the evidence of appalling and disgusting human rights abuses in Abu Ghraib prison in Baghdad for which there is and can be no excuse whatsoever."

"These images and the evidence which they portray are a shame on all of us, they are utterly shameful, disgusting, and disgraceful."

Straw also put himself at odds with Downing Street and the Ministry of Defence yesterday when he warned that ministers should have been made aware of the reports detailing abuse.

The Times says that "senior ministers" and Downing Street advisers are dismayed at how the abuse of prisoners has undermined the moral case for the occupation of Iraq.

One "senior government figure" said: "There is an overwhelming political imperative to say in public what we have been telling the Americans privately for some time. Everyone is very bitter and unhappy. We feel very let down. We are taking awesome political hits."

However, the prime minister is purported to have told allies that distancing himself from the Bush administration would be a mistake.

"You can either grandstand on this kind of thing or you can continue to have influence," a Downing Street source said yesterday.