[Undertoad]

Belmont Club:

These coordinated attacks are, technically speaking, at far higher level of sophistication than the Madrid attacks of 3/11 which involved a single train. The attack on London was a "time on target" attack which required simultaneity so that one incident did not compromise the subsequent. By implication the personnel involved received some degree of training and planned the operation in sufficient secrecy to prevent British security services from getting wind of it. The six attacks probably mean that a minimum of forty persons were involved, if those in support roles are included. The attackers must have an egress plan or access to safe houses where they can weather the inevitable crackdown.

But the good side of it:

Additional reports from the BBC suggest that the number of casualties will be comparatively small. From the amount of damage caused, the explosive devices used appear to have been in the tens, rather than the hundreds of pounds. This is good news. It also means that the enemy has not grown in overall capability since the days of 9/11 and 3/11.