Francois, I suspect that the vast majority of us were far enough away from the incident not to have been involved, directly. However, I also suspect that whilst we will put a brave face on it and try to just get on with things the best way we can, it will be another "layer" of grief and fear that we will carry around.
I've worked in the City of London since 1999 and commute to Liverpool St. I worked immediately next to the space left following the IRA bombing of the Baltic Exchange on St Mary Axe. The building I worked in (28 or storeys of glass) was literally shattered and I managed to see the photos of the devastation and speak to some people who were working late, the evening the bomb went off.
At 7/7, I had a team member on a bus that was 100 metres or so behind the one that was blown up at Tavistock Square. He and another colleague had just missed that bus. That morning, I was visiting a broker just a couple of hundred yards from Aldgate tube station. The meeting was called to a halt and, as I left, I saw the emergency vehicles arriving to start dealing with deal with the carnage. Walking back to my office, the randomness of it all struck me and it remains with me.
Even years ago in 1980 when I worked in Manchester, I was in a building that kept getting bomb alerts and evacuations. It only became evident as I left in 1984 that there was a Home Office team working in the building and that was where the files for "H Block" IRA prisoners were kept. A few incendiary devices were actually found in the building.
London feels like an easy target as it has so many stations and airports via which home-grown and imported nutters can arrive to commit whatever atrocity in the name of whatever ideology or perverted religious belief. My guess is that the majority of those likely to be the lone nutters like the attack yesterday are already here and were probably born here.
We all know the authorities are doing their best to prevent and mitigate the effects of such acts but, obviously, there's no realistic way to protect 100%