Balkan Explosives in London Blast?

The London Times is reporting that the explosives used in the London terrorist attacks were possibly imported military-grade high explosives:

Similar components from the explosive devices have been found at all four murder sites, leading detectives to believe that each of the 10lb rucksack bombs was the work of one man. They also believe that the materials used were not home made but sophisticated military explosives, possibly smuggled into Britain from the Balkans.

“The nature of the explosives appears to be military, which is very worrying,” said Superintendent Christophe Chaboud, the chief of the French anti-terrorist police, who was in London to help Scotland Yard.

I guess I might have been wrong when I said: "There also seems to be a relatively low number of fatalities considering the density of humanity in the areas targeted, and I am forced to think that these were low-grade explosive devices, quite possibly something like blackpowder pipe bombs like those used by American anti-abortion fanatic Eric Robert Rudolph. As horrible and tragic as the deaths and injuries are, the number and severity of wounds doesn't seem to indicate that military grade explosives were used. If Semtex or C4 or other military grade explosives had been used, I would think that the casualties would have been far, far worse."

I'd be glad to be wrong on this, but it still doesn't explain how forty pounds of military explosives managed to cause so few casualties in such a densely-packed environment. It could have been far worse. It should have been far worse. London was very lucky.

Or perhaps, just perhaps, someone was looking out for London.