Campaigning lawyers are also seeking a further two inquiries with wide-ranging remits to investigate allegations that UK forces abused and unlawfully killed Iraqi civilians while they controlled parts of southern Iraq.
British troops ended combat operations in Iraq in April 2009 after a war that lasted over six years, claimed the lives of 179 UK personnel and cost more than £9 billion.
The overarching Iraq Inquiry, chaired by retired senior civil servant Sir John Chilcot, has delayed publication of its final report into how Britain came to join the 2003 US-led invasion that toppled Saddam Hussein and the conduct of the conflict.
The inquiry issued a statement in November saying it would need at least until the summer of 2012 to complete its massive task, citing the difficulties of declassifying secret Government papers to quote in the long-awaited report.
Sir John and his panel focused on the decisions made by top politicians and officials, hearing evidence from ministers, diplomats, spymasters and military commanders.
They are widely predicted to be scathing about the way former prime minister Tony Blair led the country into war despite serious questions about the legality of military action.
Meanwhile, another public inquiry is set to get under way in 2012 after being held up by the logistical difficulties of assembling evidence.
The Al-Sweady Inquiry is examining claims that UK soldiers murdered 20 or more Iraqis and tortured others after the "Battle of Danny Boy" in Maysan Province, southern Iraq, in May 2004.
The Ministry of Defence vigorously denies the allegations and says those who died were killed on the battlefield.
The inquiry has appointed a team of retired British detectives to investigate what happened from scratch after an earlier Royal Military Police inquiry was judged to be inadequate.
Solicitor Phil Shiner, who represents the alleged Iraqi victims, expects there will be further delays before counsel to the inquiry, Jonathan Acton Davis QC, makes his opening statement about the evidence in the case.
He said: "There is no sign of it opening because we have found hundreds of thousands of relevant documents, in particular all the emails from theatre (in Iraq) back to PJHQ (the military's Permanent Joint Headquarters) and they have got to go through all of that.
"I won't be surprised if the oral hearings in the Al-Sweady Inquiry don't start until the summer."
One public inquiry into Britain's involvement in Iraq between 2003 and 2009 - covering the brutal death of father-of-two Baha Mousa at the hands of British soldiers in Basra, southern Iraq, in September 2003 - has already released its report.
Mr Shiner, from Birmingham-based Public Interest Lawyers, is behind attempts to force the Government to hold two further inquiries into other allegations against UK troops.
More than 100 Iraqi civilians who say they were abused by UK forces between March 2003 and December 2008 won a legal battle at the Court of Appeal in November that they hope will lead to a detailed investigation into their claims.
The MoD argued there was no need for the inquiry into the UK's detention policy in south-eastern Iraq because it has set up the Iraq Historic Allegations Team (IHAT) to look into the accusations.
But three appeal judges ruled that IHAT, made up of civilian investigators and members of the Royal Military Police, lacked "the requisite independence".
The MoD is seeking permission to take the case - referred to as "Ali Zaki Mousa" after the lead claimant - to the Supreme Court, the highest court in the land.
But Mr Shiner predicts this move will fail, adding: "Sooner or later there will be that third inquiry (into abuse allegations)."
A Ministry of Defence spokeswoman said: "We contested the application for a single public inquiry into allegations that Iraqi civilians were abused by British soldiers in Iraq and our view remains that a public inquiry is not necessary or appropriate at this time.
"A costly public inquiry would be unable to investigate individual criminal behaviour or impose punishments. Any such inquiry would arguably therefore not be in the best interests of the individual complainants who have raised these allegations.
"The MoD has set up the dedicated Iraq Historic Allegations Team to investigate these allegations to establish their truth or otherwise, identify any action that needs to be taken and, should it uncover criminal behaviour, provide the proper means to deal with it.
"The Court of Appeal did not order an immediate public inquiry but we are carefully considering the judgment they made and remain committed to investigating the allegations fully."
Mr Shiner also plans to petition the Supreme Court to revise a June 2007 Law Lords ruling in the light of a recent European Court of Human Rights (ECHR) judgment with the aim of bringing about another inquiry into alleged unlawful killings of Iraqis by British troops.
In July the Strasbourg-based ECHR's grand chamber dismissed claims by the British Government that UK forces were not governed by Europe's human rights convention in Iraq because they were beyond its jurisdiction.
The case - named after Hazim Al-Skeini, who was shot dead by a British soldier in the street in Basra in August 2003 - focuses on the deaths of six Iraqis during the UK occupation of south-eastern Iraq between May 2003 and June 2004.
Mr Shiner said: "We will be going back to the Supreme Court saying, 'here's the grand chamber judgment'.
"In doing so, we will get an inquiry into the unlawful killings in Iraq, of which there could be hundreds if not thousands."
The solicitor has also asked Director of Public Prosecutions Keir Starmer QC to consider bringing charges against 25 former and serving members of the British armed forces over Mr Mousa's death.
PA
