I left home on Wednesday morning to hear Tony Blair deliver his evidence to the inquiry committee. My wife, Sally, did not travel with me as she had been seriously ill, through the stress and strains of the past six-and-a-half years since our son, Lance Corporal Tom Keys, was killed in Iraq along with five Royal Military Police colleagues. Their deaths had been particularly horrific as they had fallen into the clutches of a raging 500-strong mob.

My plan had been to depart on Thursday, but I had received requests to come to London on the Wednesday to do interviews for CNN news, a German TV ­station and Dutch radio. Little did I know this was a precursor for the frenzy of media interest that was about to descend on bereaved family members.

Wednesday afternoon:

The circus begins in St Stephen's Square. Al Jazeera TV requested an interview. It was particularly keen to see photographs of Tom. I had brought a collection of photographs with me and they were placed on a bench in the green that faces parliament. As I stood back to let them take their photos, the sun shone across the bench and lit Tom's smiling face as he looked towards the houses of parliament. For the press it was just another part of their job, but for me it brought a tear to my eye as I reflected on the fact that Tom was looking towards the building where the decision was made that would result in his death.

I was keen to watch former attorney general Lord Goldsmith deliver his afternoon evidence to the Chilcot inquiry and was fortunate to gain a seat in the hearing room so I could sit behind the man who made the ultimate, final and controversial legal decision. It struck me that such a diminutive figure has the power to make such huge decisions. One man against a whole army of legal advisers, headed by Sir Michael Wood, who were all saying that the war, in their opinion, was not legal. It made me think of Jeremy Paxman's comment on the legality issue, when he said he could not find one lawyer in the whole of the country to defend Goldsmith's legal arguments for the war. I thought that summed it up.

Thursday morning:

I took off to the Imperial War Museum. Having viewed most of the military exhibits, I went to the upper floors, to the very sombre genocide and Holocaust sections. This proved not to be such a good idea, as it left a profound impression on me, which I constantly reflected on as I walked back to the hotel.

One image showed six Jews being lined up for summary execution by firing squad. Other bodies lay behind them. One could clearly see the expressions on the faces of those six men as they were about to die. Some stood firm, shoulders back, chest out to await their fate. One young man, on the end, who could only have been about 16, had one hand across, protecting his heart, the other reaching out towards the firing squad, his face in anguish, as he pleaded for humanity.

It made me reflect on how the six RMPs died. How did they meet their fate in that filthy back storeroom, when they were overwhelmed, without ammunition and knowing they were doomed? Some reports had said one of the redcaps was holding up a photograph of his baby in the hope that it would result in some show of humanity from the eight killers at the head of the mob who had entered the room. They just shot him through the hand.

All six redcaps received beatings with rifle butts and were shot several times. Tom had 31 bullet wounds. Other postmortem reports suggest that when another man was lifted from the ground, bullets fell from a huge hole in his back, he had been shot that many times. Again, going back to the Holocaust image, I wonder constantly what the expression was on Tom's face as he met his brutal end. Though advised not to, I viewed Tom's body in the mortuary on his return. I opened his eyelids, and wondered what the last images those once green, beautiful eyes saw. They had now just become like two milky white marbles, owing to the passage of time.

Returning to the hotel I didn't have much of an appetite, and just felt like a stiff drink. A message had been left, asking if I could write a press statement to read out on behalf of the families of the fallen, as some were not comfortable giving interviews. I agreed, but since I am something of a perfectionist it gave me a sleepless night. I had written the first draft, and then retired to bed, going over it in my mind. I woke up at 1.30 to ­practise its delivery, found I was not happy with its content and decided to polish. I was still not totally happy by 2.30 but decided it would have to do. One lesson that could certainly be learnt above all is that never, never again should a British prime minister be allowed to lead our proud and gallant armed forces into a war in such a shambolic, catastrophic way, based on lies, falsehoods and deceit. Such conduct is a betrayal of the trust of the armed forces. Tony Blair, you have brought disgrace upon the honourable position of a prime minister. Never mind international law courts: you have been judged by us today and found wanting.

Friday morning:

I trudged through the morning rain, worrying that I would not be able to give a good account on this long-awaited day. It would be fair to say that I felt miserable and dejected, thinking of happier times with Tom. Approaching the conference centre, I could already hear protesters chanting. A helicopter droned continually overhead; the circus had begun.

As I neared its perimeter, I was met by a sea of fluorescent police jackets. TV crews, press vans, photographers, the whole melee of an international media frenzy had descended on a very small area, on the forecourt of the QE2 conference centre. A maze of barriers had been erected which one had to negotiate, just to get to the centre's doors.

Inside the inquiry, and realising I had yet to go through the airport-style security to gain entry to the hearing room, I asked an official where I should pick up my pass. Unfortunately the "jobsworth" I asked was insistent that I should join the back of a long queue of the general public, standing outside in the pouring rain, waiting for the security clearance I knew I already had if I could only find my pass.

Refusing to join the back of the queue, I saw another family member, Rose Gentle, with her husband, already wearing their passes, and they directed me to the appropriate desk and then on to the relative calm of the families' room. After a short rest and a welcome cup of coffee, we were told that those going into the hearing room had 10 minutes to pass through additional security in order to take up their seats. The whole security aspect had taken on the tone of visiting royalty, in comparison to the relatively low-key security I remembered from Goldsmith's hearing on Wednesday. Previously, on talking to a police officer, he had remarked that security for Blair's appearance had cost in excess of a quarter of a million pounds.

Morning session:

My pass was for the afternoon session in the hearing room, so I was now able to watch the morning proceedings from the family room. There was anticipation in the room as we watched Blair enter, flanked by two burly bodyguards. I noted one remained seated close to him and the other remained standing, facing the public gallery, as there had been rumour of plans for shoe-throwing akin to the incident during George Bush's final visit to Iraq.

Blair strode confidently to his chair, sat down, adjusted his microphone, said good morning to the committee and opened his well-prepared pages. This was the moment that I had waited for six-and-a-half years since Tom's death. I was not anticipating any revelations and expected a cool calm delivery of his evidence, and my expectations were met.

His first 10 minutes did appear to be a little nervy and shaky, but he soon got into his professional stride. I felt he already had the measure of the panel and could easily cope with its level of questioning. Indeed at times it was somewhat reminiscent of him delivering his rhetoric from the dispatch box at prime minister's questions, with gesticulating arms and all the aplomb of an accomplished orator. At times I was willing the panel to interrupt him and bring him back to the point in question, as it seemed they had allowed him to get on his "soap box" and deliver his lines.

He'd become really confident now, and was in his stride, flowing easily. I wondered if he was arrogant enough to believe he could have this panel for breakfast. It appeared he had them where he wanted them and could take them off on a tangent, and return as he so desired. For me the morning session offered nothing new and was just confirmation of previous evidence. I was somewhat relieved when the lunch break came.

My mobile had been plugged in to recharge its battery, and on turning it back on it buzzed and beeped continually for five minutes as messages filled my voicemail quota. With other family members I left the centre feeling obliged to meet interview commitments. I don't know why I couldn't say no.

Afternoon session:

The committee took their seats and gave a warning to the relatively small public gallery about conduct during proceedings. I reminded myself to remain firmly gagged as I had no wish to be ejected. Blair entered in the same confident manner and took up his seat. Rose Gentle remarked to me at lunch time that, when Blair had entered for his morning session, his hand was trembling slightly as he unscrewed his water bottle to take a drink. Seated behind him now I looked over his shoulder to see if there were any signs of the earlier nerves. No, they were long gone: this was now the arrogant Tony Blair who knew he had nothing to fear from this inquiry. I felt that they couldn't challenge him.

Looking at his notes in front of him, I could see there were several markers on the pages and according to the question he could deftly go to the appropriate page in his notes where he would find a reference to give another long-winded answer. Seeing him flick backwards and forwards to his notes and ­easily find all the relevant sections, I suspected that he must have asked the committee beforehand for the list of questions that they were going to pursue. He had all his ammunition ready before he was ­challenged.

Again the afternoon session was reduced to the sound of Blair delivering his evidence, punctuated with the ­repetitive phrases, "I believe" and "my judgment". Where this became particularly significant for me was on the intelligence issue, when he was challenged on his delivery of the "intelligence, as assessed beyond doubt, of Saddam's WMD capability". By the nature of its being assessed, it cannot be beyond doubt.

I thought, "They're going to get him here. How is he going to wriggle out of this one?" In his reply he stated that he did believe beyond doubt the assessed intelligence. In his judgment, he believed it. So it's a bit like questioning somebody's faith. I might believe beyond doubt that there are fairies at the bottom of the garden, but that doesn't make it true. But that's how he got out of it. I cannot describe my frustration that he was able to dodge his misrepresentation of the truth so easily.

Much of the afternoon continued in the same vein without any revelations but I did mark on my notes the word "naive" when he said, "We thought that, if we removed the top tier of government, there would be a functioning administrative level below." What did he expect? If you removed Saddam, there would, of course, be a power vacuum and complete breakdown of law and order. He went on to say: "It was the influence of external forces that caused the main problem." Cross-border terrorism: he hadn't planned for that. Again I marked in my notes, "Naive! Without government Iraq would become a fermentation that would breed terrorism." And I marked again in my notes, "Naive! The local darts team down at the pub could have planned it better."

Blair was then questioned on the death toll, which he agreed was in excess of a hundred thousand Iraqis. His trite response was: "Well, it isn't us that's killing them, it's the insurgency." I gasped — I couldn't believe it. He was party to creating that environment where insurgency could thrive. Didn't Blair realise this? I thought back to adjutant general Sir Freddie Viggers, whom I have met on several occasions: in his evidence, he remarked that the invasion was run by a bunch of amateurs and, when questioned by Chilcot as to what level, Sir Freddie replied it went right through to the very top, at ministerial level. I reflected on this and thought how right he was.

Blair remarked that it was a lesson learned, and Chilcot remarked: "Well it was an expensive lesson, Mr Blair." Blair's response was: "If we learn one lesson, it is that occupying a failed state, you will be there for the long haul." Again I wrote, "Naive".

As well as frustrated, I was starting to realise how angry I was, and that I must remained tight-lipped. I wanted to shout out, "Didn't you realise what you were bloody well doing? Didn't you bloody well realise the consequences of your actions?" Silly as it sounds, close up you start to notice personal things, like how thin he looked. His immaculate hairline and shaven neck looked like a waxwork figure. It was almost as if he realised people would be viewing him from the back. I remembered rumours about how fastidious he was about his hair. It is shameful that he didn't apply the same diligence to post- and pre-war planning.

As it was coming to an end, I was beginning to feel numb. Six-and-a-half years have taken away the passion of the anger, and I have become pragmatic and resigned to the fact that Blair will walk through all this Iraq controversy with impunity. Iraq had taken on the context of a runaway train, and no one seemed able to stop it. At the end of the session, Sir John Chilcot asked Blair whether he had anything else to add, his sharp reply of "No" was followed by Chilcot asking: "Do you have any regrets, Mr Blair?" After a few rambling sentences, Blair said: "No. No regrets."

At this stage, some members of the public could contain themselves no longer. One man stood up and shouted: "Come on, Mr Blair, there must be one regret." Two bereaved mothers broke down in tears; another man shouted: "Surely, Blair, you regret the death toll?" This was the only time during the whole day that I became emotional: seeing the two mothers crumple into the arms of relatives, sobbing; seeing Tony Blair stride out with arrogance, without even a glance at the hurt he had caused. He left the room to the strains of one man shouting, "Murdering bastard Blair!" I noticed Chilcot, as he left the room with the other members of the committee, look and take note of Theresa Evans, who was sobbing uncontrollably, clutching a little locket, bearing her son's photo­graph, the rose she had been wearing now lying crumpled on the floor. To my amazement, I had remained silent.

Home:

On the train home that evening, I regretted not speaking out as Blair left. I had prepared words, but the sight of the mothers breaking down choked me up and I could not find the voice. I wanted to say: "Blair, look at me! You are a pathetic excuse for a man. You have brought shame upon yourself and shame upon the armed forces. This isn't over yet." Although I knew it was.