'Mr Blair, I hold you personally responsible for my son's death. You should stand down'

Paratrooper Andrew Kelly's letter to his father was written in high spirits, relaying exuberant details of a "mega war" of "storming bridges", of taking "AK fire". His excitement was also in his signoff: "When I get back, let's have a pint, maybe 10".

His father Rob Kelly, who served with the Navy for 24 years, recalled yesterday: "I read it and went out to get some blueys - airmail letters - to send from the family, and then I got a call from my ex-wife. My feelings at that point are indescribable, your worst nightmare. While I was reading his letter, my son was already dead." This morning, Mr Kelly will send his own, carefully constructed letter to Tony Blair. In it, he blames the Prime Minister for his son's death in an "unjustified" war, and will call on Mr Blair to resign.

Mr Kelly's disdain for Mr Blair is clear from the outset. He writes: "I cannot begin to explain to you how I feel about losing my son nor do I believe that you care or would understand."

But the crux of his complaint is Mr Blair's attempts to justify the war, that has ,so far, seen 42 British servicemen lose their lives. Andrew, at 18, is the youngest to die.

Mr Kelly, 54, now a restaurateur, tells Mr Blair: "I hold you personally responsible for my son's death as well as those of the other servicemen killed as a result of your decision to go to war with Iraq. Unless you can justify the war with Iraq, I say you should take responsibility for your decision and stand down from your position as Prime Minister of our great country to enable a person with integrity, who has the interests of our country at heart, to lead with sincerity and dignity."

A veteran of the Falklands conflict who considers himself anything but a pacifist, Mr Kelly supported his son's lifelong ambition to join the Parachute Regiment, and backed him when he went out to Iraq. But he believes Mr Blair was guilty of an inexplicable decision when he sent British troops to war against Iraq.

Mr Kelly cares little for the nuance of the 45-minute claim or the "sexing-up" of documents to support the case for military action against Saddam Hussein. He considers, though, that all diplomatic avenues were not exhausted before troops - including his boy - were sent into combat.

Mr Kelly explained yesterday: "Even if there were weapons of mass destruction, it was still no reason to go to war. We should have sent people in to find them. When Argentina invaded the Falkland Islands, we didn't declare war we just took them back.

"I don't disagree with war, and I agree that Saddam Hussein was a dictator. He should never have been in power but you have to do things properly.

"I would have always feared this could happen if my son went to war. But I would understand if someone was threatening our country. This was not the case - there was no reason to go to war."

Five days after his 18th birthday, Andrew Kelly, a "sincere, funny" young man with a "sense of right and wrong" who joined the army at 16 - headed off to the Gulf. As psyched up as one might expect of a teenager who always carried a copy of Maroon Machine - a poem that extols the fearlessness of paratroopers - he still turned to his father for advice on occasions.

Mr Kelly said: "The night before he went, we were talking about it and I said if he did go into conflict he would come back a changed person. When you are 18 years old, you have no concerns whatsoever. I said to him be prepared to be scared. Do as you are told and don't be a hero.

"There is absolutely no point when your son is going out there in saying I don't agree with it. There is no way I would do that to my son. He had to have the confidence that his family was behind him."

Ten weeks later, Mr Kelly watched as Private Kelly's coffin, draped with the Union flag, was borne into St Mary and St Julian Church at Maker in East Cornwall.

Serving with the 3rd Battalion Parachute Regiment, part of the 16 Air Assault Brigade, the teenager from Tavistock, Devon, helped to secure Basra and the surrounding oil fields during the early weeks. "When war ended, I thought 'Thank God my son is safe'," said Mr Kelly.

But shortly after 6am on 6 May he died at the unit's Basra base after an "accidental discharge" of a weapon - a matter which is still being investigated by the army authorities. His last letter home to his family ended with the bullish postscript: "Paras don't die, they go to heaven and regroup."

His father concluded yesterday: "This is not a vindictive letter [to Tony Blair]. It is not a letter of hate or anger - it is just a letter of feelings, very strong feelings. My son would be here now if war hadn't been declared."