But until the Citigroup building and another of them on the Docklands has planes from LHR flown into them and another into Parliament or the UK equivalent to the Pentagon, it's hard for others to understand the undue "skittish"-ness.
I suppose the UK's experience of explosive destruction is limited. Just the Blitz, WW2, the IRA and various middle-eastern parties. I seem to remember year upon year of having bits of London go up in a bang, or being rushed out of shops, tube stations and theatres because there had been a bomb threat, an experience not familiar to most Americans.
The UK's main response was to remove public litter bins. If only we'd know how to overreact properly!