Fear is horrible thing mostly caused by ignorance. The press manages to terrorize people again.
Liquid gasoline is not an explosive. It is an incendiary. Gasoline fumes can explode but even if it "explodes", it lacks the power of of "true explosives" like dynamite, gun powder or Semtex. Simply put, the London luxury bombs (...hey they put them in Mercedes Benzes not Fords) are crude, ineffective and highly unlikely to kill hundreds of people unless there was a rave planned directly around the cars.
The cars were reported to have 2 sealed 25 gallon canisters of gasoline, a propane tank and nails. The car windows were also closed. Hint to press: Anything incendiary requires oxygen to work. Also sealed propane tanks do not explode unless there are structural problems on the tank itself and the propane gas escaped and is within an optimum environment to ignite and explode. The press can test the theory on 4th of July. My guess is there won't be a single propane tank explosion in the US on 4th of July. The cars would have been the most poorly designed incendiary cars much like a Cadillac Escalade or any large SUV.
What do we really have? Quite possibly 2 or more Al Qeida or Real IRA knuckleheads, disgruntled, unemployed, alienated, uneducated and radicalized with a Rambo and Die Hard DVD collection. They are evil dumb asses who wanted to terrorize London and the world but since they surely flunked chemistry, they would have failed. Their crude luxury bombs would have failed.
The Al Qeida or Real IRA wannabes failed. Chemistry and physics were not on their side. They did succeed in getting the inept press led by Faux News to to characterize the cars "as bombs that would have killed hundreds of people."
The press managed to scare and terrorize people again.