The government has infuriated MPs by appearing to block a Commons debate on the anniversary of the Iraq War.
The group has written a strongly-worded letter to parliamentary authorities, saying the public has a right to hear from MPs on the controversial decision to invade in March 2003.
MPs including the Green Party's Caroline Lucas, former Liberal Democrat leader Charles Kennedy, Conservative Rory Stewart - who served as the British deputy governor of southern Iraq, and Labour's Paul Flynn, said it pitched for a parliamentary debate via the backbench business committee.
But although it was agreed in principle, the government has refused to make the necessary time available, the group said.
In a letter to the Leader of the House Andrew Lansley today, signed by Lucas, Kennedy and Flynn, the group said the public had a right to know more about the process that led to the UK's involvement in the war.
Lucas, MP for Brighton Pavilion, said: "Ten years on from the vote that took us to war in Iraq, the British people have a right to hear what Parliament has to say about the legal and Parliamentary mechanisms that led to the decision, what occurred during the war, and the legacy of the conflict for the people of Iraq today.
"Whatever position this Government takes on Iraq and the Chilcot Inquiry, to be published later this year, it is critical that the public does not see Parliament just sitting back and ignoring this 10-year anniversary milestone.
"We owe it to the servicemen and women and all those who lost their lives to this devastating conflict to carefully examine what happened 10 years ago, in order to prevent the same terrible mistakes being made in future.
"The decision not to give time for an Iraq debate looks dangerously like government is doing its best to shut down parliamentary scrutiny of arguably the most damaging foreign policy decision in recent times."
A YouGov poll conducted to mark the anniversary of the war has found that more than half of Britons believe Tony Blair was wrong to invade Iraq, while 22% think he should be tried as a war criminal.
The survey found that 53% of of those questioned believed the invasion was a mistake and only 27% believed it was the right thing to do.
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