A British court today sentenced to life in prison the five "Fertiliser Plot" men, mostly British-born and Pakistani-trained militants who were planning to blow up targets in London (including a nightclub, power plants and shopping mall) with half a ton of ammonium nitrate and other substances. As a consequence today the MI5, finally free to disclose its information without jeopardizing the case, released new information about the links (some of them already known) between the Fertiliser Plot and the 7/7 bombers.

The information is quite detailed, but, in a nutshell, the MI5 revealed that two of the 7/7 bombers, Mohammed Siddique Khan and Shehzad Tanweer, had been seen with Omar Khyam and other Fertiliser Plot members in early 2004. Khan and Tanweer were taped discussing ways to raise money through fraudulent schemes but, since no specific mention of an attack was made, the MI5 decided not to investigate them. As the Intelligence and Security Committee's Report into the London Terrorist Attacks has already pointed out, "in light of the other priority investigations being conducted and the limitations on Security Service resources, the decisions not to give greater investigative priority to these two individuals were understandable." Given its limited resources, MI5's decision not to divert human resources to investigate individuals that, while clearly interested in jihadi activities and intentioned in committing crimes to support them, did not constitute an immediate threat, was probably a sound one and second guessing it today is as easy as useless.

But here lies the problem: the MI5 should not have been stretched so thin. As the MI5 correctly points out, "when the fertiliser plot took place it was one of 50 networks of which the Service was aware" and the agency could not possibly start a new investigation. The MI5 was simply understaffed to deal with a domestic threat of that magnitude. And the problem is not just a British one. 3/11, the other major attack perpetrated by al Qaeda-inspired networks in Europe, is characterized by eerily similar circumstances. Jamal Zougam, one of the men currently standing trial in Madrid for his crucial role in the bombings, was also known to local intelligence services, but because of their lack personnel, no detailed investigation on him could be carried out.

In the summer of 2001, in fact, Spanish authorities had begun monitoring the conversations of several Islamic fundamentalists operating in the Madrid area, but Zougam's telephone was tapped only briefly. When most of the members of the cell were arrested in November 2001, Zougam was not charged. Even though Yarkas, the leader of the cell, had frequently spoken with him and had often used his shop to make phone calls or to meet other members of the network, there was no evidence that Zougam had committed any crime. Zougam's name surfaced again after the May 2003 Casablanca bombings. Mohammed Fazazi, the Beniyach brothers, and several other associates of Zougam were either arrested or investigated by Moroccan authorities cracking down on Islamic fundamentalists operating in the country. Zougam, who had returned to Madrid three weeks after the bombings, was also investigated, but there was not enough evidence to charge him. "Morocco informed the Spanish that he went to Spain and that he was a quite dangerous person. There was no evidence against him in Morocco, but they asked Spain to investigate him," said frustrated a Moroccan official.

It was common knowledge that Zougam was involved in radical activities, but investigators lacked sufficient evidence to charge him or even to maintain a constant tap on his phone. Because the tapes of his conversations were given low priority, they were set aside for months. And since the Spanish counterterrorism authorities had only seven part-time Arabic translators, who were overwhelmed by their workload, most of the tapes were not translated at all.

Cases like those of the 7/7 bombers and of Jamal Zougam show that, in most cases, terrorists do not operate in a vacuum and have at least superficial contacts with likeminded individuals. While these contacts do not warrant an arrest (France, with its broad and often criticized "conspiracy in relation to terrorism" charge might be, in a way, an exception to this), they should be enough to raise the attention of intelligence services. Today things have improved and in both Spain and the UK the intelligence services have been given additional funds and manpower. London and Madrid have painfully taught us the importance of not underfunding intelligence services.