The resemblances between the attacks in Madrid and London are so obvious that comment appears superfluous. Actually, the differences are more revealing than the resemblances themselves.
In Spain, the attacks were a few days before the lections of March 14, 2004. The polls announced the victory of José-María Aznar and People’s Party, but the winner turned out to be the Spanish Socialist Party, thus contaminating the understanding of the event. Sixteen months after the attacks, a Spanish parliamentary commission made an inquiry of what had happened by focusing on the policies of Aznar’s government. He was criticized by the socialists who claimed that he precipitated in accusing ETA for electoral purposes. The conservatives, in turn, have devoted to defending their records, and have raised questions about the darkened areas in the ties between ETA and the terrorists, and the suspects and Moroccan secret services.
At the same time, the investigation has proceeded at snail’s pace because, obviously, the main suspects were blown up on the outskirts of Madrid. The people who were arrested did not have the authority to plan the attacks. The investigation is teetering and the attacks have intensified the tensions and the existing divide in the Spanish society.

The Guardian (United Kingdom)

Madrid’s vanished horror”, by Víctor de la Serna, The Guardian, July 8, 2005.