The families of two servicemen who were killed in the Iraq conflict said Tony Blair's ticket for the Iraq and Afghanistan memorial service should have gone to bereaved families.
The former prime minister was among the guests of honour at the service at Horse Guards Parade in London.
But his presence was questioned by Diana Fitzgibbon and Gerry Cartwright, from Clapham, south London, whose 21-year-old son Lance Corporal James Cartwright was killed in a tank accident in June 2007.
Mr Cartwright, 64, said: "I've got issues with Tony Blair and his government. I would like to have seen him."
Asked what he would have said to him, he said: "Goodbye is all I could have said to have him. And 'why did you do that?' It's just a terrible waste.
"Probably they could have got another mum or dad or wife or husband (here today) to take his ticket."
Ms Fitzgibbon, 59, added: "I feel the same, but it's not going to bring my son back.
"Was it all worth it? I don't think so. They are still at war with each other, aren't they."
Their frustrations were echoed by Tracey Hazel, from Northumberland, whose son Corporal Ben Leaning, 24, of the Queen's Royal Lancers Battle Group, died in southern Iraq in April 2007 alongside Trooper Kristen Turton when their vehicle was hit by an improvised explosive device.
Ms Hazel, 50, said: "It wasn't worthwhile. It achieves nothing, and it also ended my son's dad's life, which made me more angry.
"I always think anyone's innocent until proven guilty, but the Chilcot inquiry just proves different."
Asked about Mr Blair's presence at the ceremony, she said: "I honestly think somebody else should have had his ticket, like one of the parents."
They also said that while the service had been "absolutely beautiful", and it was nice for Prince Harry to have spoken with them and offered his condolences for their loss, it was "upsetting" and "a shame" that more bereaved families could not attend because of a restriction on numbers.
Mr Cartwright said: "It (the service) is a lovely thing to do, and gives you a warm feeling. I just get a warm feeling doing it.
"But it's a bit upsetting that, because we've seen so many families that didn't get invited for whatever reason, a lack of numbers.
"We just feel lucky and guilty at the same time that we got invited."
Mr Cartwright said it would have been "wasteful" to have passed up on the opportunity to attend, saying: "We are representing those that couldn't come.
"Maybe we're here for the others as well - we'll send them some pictures."
Ms Hazel said: "The service was absolutely wonderful, but now I feel bad for the other parents who couldn't come.
"I feel very guilty for being here, but I want to be here so I have got mixed feelings.
"We have to represent, but it does make you feel guilty because I don't know how I would feel if other people were here and I wasn't.
"But I would feel dishonourable to my son if I didn't come."