The insidious car bomb detected in London’s Picadilly Circus area is a bad omen on many fronts:

Police thwarted an apparent terror attack early Friday after an ambulance crew reported seeing a smoking car parked near Piccadilly Circus that turned out to be packed with gasoline, nails, gas cylinders, and a detonator.
The explosives – safely defused by a bomb squad – were powerful enough to have caused “significant injury or loss of life” – possibly killing hundreds, British anti-terror police chief Peter Clarke said.

Easily obtainable materials stuffed into a car and parked along a crowded street somewhere. There is no way to prevent this kind of attack without sheer luck, as was the case here. There is not way to regulate these materials and no way to stop cars from being on crowded streets (that is why we have streets). If this kind of thing spreads we are all in for a truly terrible future. First will be the waves of killing and then will come the crack down on our freedoms to try and control things enough to minimize the killings.