From the moment that armed police ran into my tube carriage, I have been - like it or not - part of a major public event. What I witnessed has been described numerous times, sometimes in ways I recognise and sometimes not. But one thing that has been consistent has been a sense that the shooting involved De Menezes and the police but no one else. Until CCTV footage of the incident was released, you would have been forgiven for forgetting this happened in a public place.

My memory of the day is full of people. Bodies pushing to get out of doors, a desperate scrum at the foot of the narrow stairs, the sound of screaming from other carriages. With the witnesses removed, the shooting can be described in impersonal terms. And while this may be the clearest way for a court to investigate, I don't think it is the best way for this terrible event to be remembered.

If you take the people away, you lose the means to understand the true horror. I was there; I can tell you: "I watched someone die on a rush hour tube train. His body was left in a pool of blood on the floor." To fully comprehend what happened and begin to put things right, the witnesses need to be back in the picture.

So why have we been so quiet? The Independent Police Complaints Commission advised witnesses not to meet or communicate, or talk to the press, for fear of interfering with future legal cases. But while evidence from civilian witnesses appears in this week's IPCC report, none was called to give evidence at the recent trial. The best we could hope for in court was to be represented through other people's words.

I have tried very hard to be a "good witness", but the odds have not been in my favour. I gave my first statement to police with no idea that what I was describing would turn out to be so contentious. At the time it seemed simple - the police had caught a bomber. I was in shock and wanted to go home, but first of all I wanted to help. If I hadn't spoken to the police on the day and had waited to speak to the IPCC, my evidence today would be stronger. As it is, the statement I eventually gave to the IPCC will always stand alongside that first rambling statement given in shock.

I was surprised to learn that the firearms officers made their statements together and not until some days after the event. Apparently this is standard procedure, designed to help them give the most complete account they can once the effects of shock are wearing off. Civilian witnesses were not afforded this luxury, and this shows in our accounts. How can it be that our evidence, from the very beginning, stood less chance of being coherent and credible than that of the officers who shot De Menezes?

I have trusted that, in keeping quiet and apart from other witnesses, I have been doing the best I can. But it is beginning to feel as if I've been protecting information that has no legal purpose. When civilian witnesses finally speak in court at the delayed inquest - nearly three years after the event, with all the information from the trial and two IPCC reports in the public domain - what use will our testimony be then? If the firearms officers can confer, why can't the witnesses? If the police can give accounts to the media, why can't we?

There is something inhuman about the response to this incident. You can see it in the attempts to paint De Menezes as partly responsible for his death, and in the way his family has been isolated and ignored. And you can see it in the awkward position the witnesses hold. Unlike others affected by major incidents, we are unable to meet or mark anniversaries together. These are things that can bring meaning to seemingly senseless events, yet we and, crucially, the De Menezes family are denied them. Instead, we are kept separate and silent, made to feel that what we saw should not be spoken of, that we cannot contribute to making things right.

I have left flowers at Stockwell station two years in a row, wondering if other witnesses are doing the same. There are, certainly, lots of flowers.

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