The fact that home-grown suicide bombers known to the authorities were able to hit Brussels precisely at a time when the city was saturated with police and intelligence services hunting terrorists has led to soul-searching in Belgium.
There could be no denying mistakes had been made when two ministers offered to resign over failings in the tracking of the Bakraoui brothers, who blew themselves up on Tuesday at the airport and metro.
The prime minister, Charles Michel, refused to allow the key ministers to stand down. Nevertheless, there was a damning revelation that one of the suicide bombers, Ibrahim el-Bakraoui, who Belgian authorities initially said was known only for criminality, had in fact been flagged by Turkey as a “foreign terrorist fighter” last year and deported to the Netherlands.
Experts in the intelligence community warned that outright “Belgium bashing” from abroad was not going to help matters. France, which is itself facing criticism at home over failings in preventing terrorist attacks, had to calm a potential diplomatic spat after its finance minister, Michel Sapin, accused Belgian officials of a “lack of will” and “maybe also a kind of naivety” in failing to handle the spread of radical Islam.
The European commission president, Jean-Claude Juncker, jumped to Belgium’s defence, dismissing accusations that it was a “failed state”.
The task of unpicking exactly what type of gap in intelligence that thesurveillance-savvy and well-organised bombers were able to slip through will take time, but it holds the key to preventing further Islamic State attacks.
There is a long list of potential failings to consider. The first is how Ibrahim el-Bakraoui, who had skipped parole after serving less than half of a nine-year sentence for armed robbery, was able to leave forSyria and then be deported from Turkey as a “foreign terrorist fighter” without his domestic authorities noticing he was a militant.
At the time of the Brussels attacks, he and his brother were actively being hunted by police following a raid on a terrorist hideout in Brussels connected to November’s Paris attacks. It is not certain whether the Bakraoui brothers were the two men known to have fled from a flat across rooftops, eluding police snipers.
Only four days before the Brussels attacks, Europe’s most wanted man, Salah Abdeslam, the prime suspect in the Paris attacks that killed 130 people, had been cornered in Brussels. Police knew other dangerous suspects remained on the run, yet the Brussels bombers, who were linked to the Paris attacks, escaped detection.
Najim Laachraoui, who is believed to have been the second Brussels airport suicide bomber, had been wanted by police since December over the Paris attacks, though under a false identity that was only unmasked last week.
Laachraoui, who is thought to have been the Paris attacks’ bomb-maker, went to Syria in September 2013 in one of the first waves of jihadis to leave Belgium for the country. In February, a Belgian court convicted him in absentia for his involvement with Isis.
“If you put all things in a row, you can ask yourself major questions,” said the Belgian interior minister, Jan Jambon.
“When an attack happens, it by definition means there has been a failure,” Thomas Renard, a terrorism expert at the Egmont Institute, a Brussels-based thinktank, told the Guardian.
It is unlikely that Belgium underestimated the overall threat from terrorism and jihadis returning from fighting abroad. For several years, it has been on the frontline of terrorist cells in northern Europe and was well aware of the danger.
Per capita, Belgium is Isis’s most fertile recruiting ground in Europe. After November’s attacks in Paris, Belgian authorities shut down Brussels for almost a week, closing schools, offices and cultural centres, cancelling sporting events and putting the army on the streets as there were fears an attack was imminent.
But questions will be asked about whether Belgian analysis of specific threats was correct and whether it was watching the right people.
“It will be a long time before we know exactly what happened,” Renard said. “There is a question about whether they didn’t take the full measure of attacks being prepared in Belgium, or whether the role of certain individuals was missed.
“Or perhaps they focused on individuals considered most dangerous and missed the bigger picture of other figures involved. They could have underestimated the size and scope of the cell.”
This appeared to have earlier been the case with Abdelhamid Abaaoud, the ringleader of the Paris attacks. He was linked to the terrorist cell that was raided in Verviers near the Belgian-German border in January last year, in which the Belgian authorities said they had foiled an imminent attack. Yet Abaaoud’s importance did not seem to register, he escaped the net and later led the Paris attacks.
Belgium’s difficulties in reconciling its French and Flemish-speaking communities were illustrated five years ago when it broke the modern-day world record for the longest time failing to form a government. It has so many layers of local and federal authority that information can slip through the gaps.
The Brussels-born Abdeslam brothers involved in the Paris attacks were noticed by local police as having been radicalised and as potentially dangerous but when the information was transferred to federal police it appeared to get lost.
Belgian intelligence staff have been evaluated positively by foreign intelligence services. “They’re good,” said Bernard Squarcini, a former head of French counter-intelligence, but he felt there were not enough of them.
Figures are confidential but it is thought that between 600 and 800 people work in civil intelligence and up to 800 work in military intelligence – with perhaps about 500 devoted to tackling Isis. That could equate to a ratio of three officers per jihadi suspect who is considered dangerous. Permanent telephone or human surveillance needs more people than that.
Last month the Belgian government announced a €400m (£315m) programme to combat “terrorism and radicalisation” that included the hiring of 1,000 additional police, prosecutors, state security agents and other personnel.
As far back as November, Michel, the prime minister, said: “We have to do more, and we have to do better.” After this week’s attacks, those words seem more pertinent than ever.