Who watches the custard?

The Dr passed me "The cost of telling the truth", Neil Garrett's account of what happened after he broke the story last year that Jean Charles de Menezes was not wearing a bulky jacket, was not running, and did not vault the ticket gates.

There's something especially chilling about the arrest four times of Garrett's pregnant girlfriend - she was once held for hours without bread or water - when those who shot an innocent man eight times for... er... looking like another foreigner may not ever be held accountable. There's also been little explanation for why the media got told de Menezes was running, jumping and wearing a big coat - and worse, for where the "rapist" accusation came from.

It hardly makes you proud of the "free" society that miserly extremists want to spoil for everyone.

There is not a great deal you can do to stop people who've already decided their own lives are worth less than their "cause". Much crime prevention is about making things less easy, not impossible. I can't believe anyone joins the police force for reasons other than to make life easier, safer and better for everyone.

And since the police are exemplars of the community, we often forget that - like politicians and doctors and those folk in glossy mags - they are also human beings with the same ordinary frailties as the rest of us.

People make mistakes. People get tired. People are so caught up in nobly defending all that's obviously right that they sometimes need to be beseeched-thee in the bowels of Christ to consider the possibility that they are wrong.

Most of us can do an okay job at things - that's the law of averages. We can't all be brilliant and amazing. Mediocrity is a derogative term, but it's literally how things turn out across the board.

It was reassuring to see the huge police presence in London last summer, as it was to fill out the pubs after the memorial in Trafalgar Square. We will make a stand for what's obviously right. It might merely be a gesture of defiance, but it feels good to be able to make it anyway.

So I'm sure that most, maybe all, of those involved in the shooting made understandable errors in exceptionally difficult circumstances.

But it doesn't make any of us feel any safer when an innocent man gets shot. Nor when it turns out that all we were told about him is not actually true. Nor that the police seem to have bullied the bloke who found this out.

I also appreciate there will have been internal investigations, sincerely conducted to ensure that such a mistake can never be made again. But that's not good enough.

If the guardians of the law go unguarded themselves, how can we have any faith in them?

Even Judge Dredd, idol of a brutal, dystopian police state in a comic for boys who like killings, understands this. The lesson drummed into me as a spotty, cross teenager was that it's not enought that justice is done, it must be seen to be done.

Because without that, what happened to de Menezes could happen to any one of us. That's terrifying. Terrorists blow themselves up on public transport exactly to make us think that.

Which reminds me of Ming last week (and of Millennium who quoted him): "Human rights are there to protect all of us, and you never know when you or your family or friends might need them."