Corporal Daniel Kenyon, 33, and Lance Corporals Darren Larkin, 30, and Mark Cooley, 25, face a total of nine charges ranging from assault to forcing detainees to simulate sexual acts.
Their alleged acts were captured in photographs, which have been described by British Prime Minister Tony Blair as "shocking and appalling" and have further angered Muslim nations after the scandal of US troops' abuses at the notorious Abu Ghraib prison near Baghdad.
The 22 photographs, taken by servicemen and which make up most of the evidence against the three Royal Fusiliers, also show an Iraqi man tied to a forklift and one of the accused pretending to punch a detainee.
"The treatment of Iraqi captives as seen in the photographs violates every international safeguard relating to the treatment of civilians during war and contravenes everything that a civilised nation should stand for," the Independent newspaper said.
The left-leaning Guardian wrote that Blair had summed up the national mood in his address to parliament.
"Mr Blair spoke for all parties and the whole nation when he condemned the images of British troops allegedly abusing Iraqi civilians as both shocking and appalling," its editorial said.
"Everyone finds those photographs shocking, appalling, and there are simply no other words to describe them."
Tony Blair, British prime minister
"Few in or out of the chamber could have been in doubt about the harm and shame that the images inflict on our troops, on the government's Iraq policy and on this country's wider reputation."
In his address on Wednesday, Blair said that "everyone finds those photographs shocking, appalling, and there are simply no other words to describe them."
But he said that the vast majority of soldiers in Iraq had brought "great honour to this country" and that Britain was committed to prosecuting such crimes.
Defence lawyers have been trying to establish at the court martial, in Osnabrueck, western Germany, that the soldiers had been obeying orders when the alleged acts occurred.
They were working as part of Operation Ali Baba, set up at a food depot near Basra, southern Iraq, in May 2003, just after the end of major hostilities, to try to stop looters stealing humanitarian aid stored there.
The mission was set up by Major Daniel Taylor, who was scheduled to give evidence on Thursday until the hearing was adjourned for legal reasons that cannot be disclosed.
Taylor is said to have ordered British soldiers sent to the area, in the absence of any local police, to detain suspected thieves around the sprawling depot and "work them hard".
"The whole reason he is in the dock stems from those who gave the orders to implement plan Ali Baba," Kenyon's lawyer, Joseph Giret, told the court martial on Wednesday.
Larkin has pleaded guilty to assaulting an Iraqi by standing on him and faces six months in jail. He has denied another charge, and his co-accused have pleaded not guilty to all other counts, which have penalties of up to two years in prison. The court martial could run for five weeks.