The first hints of Diana-ism are creeping into public view. First, we have the idea of a march in London to say ... what? That we're opposed to being bombed? That we're not afraid? That we support some specific foreign policy? I don't think it's really clear. The most important thing to say is that we're not afraid, but I think any such demonstration, whatever the actual intention is more likely to suggest to the less-than-stellar intellects attacking us that they are having an effect, and that they are capable of influencing us.
The same, I'm afraid, goes for the idea of a memorial to the victims. Certainly we will have a memorial service, and I should think a discreet plaque or something, as exists for the victims of the Kings Cross fire, but a "National Memorial" to the victims, as suggested by Tessa Jowell, is counter-productive. A permanent reminder for us of the victims is also a permanent reminder for our enemies of their success -- a trivial and negligible success which deserves to be forgotten. When the enemy is defeated, then it will be time to build war memorials. Until then, whether it is a year away or a century away, the way to show defiance is to carry on as normal, not to exaggerate our losses.
None of this goes for those elsewhere who choose to show solidarity with us, and involvement with us rather than non-involvement. The people at We're Not Afraid, for example, have my gratitude, as for them there is the choice of saying "nothing to do with me, mate". But for those of us that live or work in London, any overreaction is a sign of weakness.