Between 2003 and 2009, 179 British service personnel were killed in Iraq
A retired Army officer whose son was killed in Iraq has said the government "misled" the country over the reasons for going to war.
Colin Mildinhall was speaking as he and other relatives of those killed in Iraq met officials conducting the inquiry into the war and its aftermath.
He said the UK had been "lied to" by the government over the presence of weapons of mass destruction in Iraq.
The man heading the probe said he had "an open mind" about its conclusions.
The first of a series of meetings with relatives of those killed during the UK's six-year mission in Iraq has taken place in London.
All of the bereaved have been contacted and about 50 families have said they want to talk to the committee, headed by former civil servant Sir John Chilcot.
He has said it is vital he hears from the families and made it clear their views will inform how the inquiry is conducted.
At Tuesday's meeting, former Lieutenant Colonel Mildinhall, whose son Tom died in 2006, criticised the legality of the war and the controversial claim that Saddam Hussein would be able to deploy weapons of mass destruction within 45 minutes.
"It is on this basis that I believe we were misled," he said.
"I would particularly like the inquiry to look at the whole representation of intelligence, how it was used or misused in the approach to this war.
"I believe this country has been badly let down and lied to. I would like to see some accountability."
The widow of an airman killed when his RAF Hercules plane was shot down in 2005 said politicians had to answer for the fact that his unit was "poorly resourced" and the plane itself was "worn out and ill-protected".
"There should be some political responsibility for the commitment of our forces to action," Kellie Merritt, whose husband Flight Lieutenant Paul Pardoel was one of 10 servicemen to lose their lives in the incident, said.
Among those attending Tuesday's meeting were the family of Margaret Hassan, the British aid worker who was taken hostage and killed in Iraq in 2004.
Her sister, Deirdre Manchanda, said she wanted to know whether British troops had been moved around Iraq to please the White House in the run-up to the 2004 US presidential election.
Further meetings will be held in Manchester, Edinburgh, Bristol and Belfast later this month.
The inquiry panel will also hear from veterans of the conflict in London on Wednesday, having issued an open invitation to former and current military personnel to take part.
The inquiry's chairman, Sir John Chilcot, said he wanted to know what those who served in Iraq and the relatives of those who died there believed he should focus on and to hear their concerns.
"We come to this task with completely open minds," he told the families.
"We have a commitment, both personal and collective, to review the evidence that we get objectively and each of us is independent of government."
The committee is going through thousands of government documents before holding its first public hearings later this year.
Sir John has said the inquiry, to cover events from the summer of 2001 to the end of July 2009, could continue until well into 2011.
He has confirmed proceedings will be suspended during the general election campaign, expected next spring.
It is thought that the key figures in the war - including former prime minister Tony Blair - could be questioned by the committee.
Sir John has said these sessions should be held in public unless there are compelling reasons of national security not to do so.