Quote Originally Posted by LeftEyeNine
I still think that they tried to fire up a psychological fight this time, regarding the "we do not fear" slogans..
I agree that this might indeed be the background, although I do not quited think that the "failure" was intended.
It might be that parts of the terrorist cell felt provoked by the fact that the Londoners basically showed AQ the finger and decided to go on with life instead of showing the desired reaction.
Based on that they might have decided to start a second bombing that failed either because it was rushed or because the remining terrorists lacked the expertise to prepare the bombs "properly".

This might of course be idle speculation - in the end I am glad that the tragedy did not repeat and that this failed attempt might provide the authorities with additional leads to smash any AQ cells in the UK or elsewhere.