Three and a half thousand kilometers apart, dozens of people were murdered this week in Egypt and Belgium by Daesh (the self-proclaimed IS). In the Sinai, 13 policemen died when terrorists attacked a checkpoint on Saturday and in Brussels at least 21 people were killed and scores wounded yesterday in bomb blasts at the city's Zaventem airport and Maalbeek metro station close to the EU's headquarters. While every sympathy must be extended to the families of the victims of these barbarous attacks, much less sympathy should be felt for the authorities who had every reason to be prepared for these outrages. Egypt is pretty well engaged in a shooting war with the terrorists. Its soldiers and police need to be on permanent high alert. It appears that the Sinai checkpoint was first attacked by a car bomber and then overrun by the attackers, who shot the defenders, including the wounded, out of hand. In Brussels, failure rests with the Belgian authorities. When Salah Abdeslam, the chief suspect in last November's Paris attacks in which 130 people were slaughtered by Daesh gunmen, was arrested on Friday, there was a massive sense of relief. "We've got him," crowed a government minister. Yet in the wake of this success, it is extraordinary that the Belgian capital was not once more put on the highest state of alert. After all, last year the city was virtually closed down for five days in the wake of the Paris attacks. There were two conflicting indicators. The first is that generally after a terror bust in Europe, the networks tends to go quiet, with the men of violence withdrawing deeper into the shadows to avoid the likely dragnet. But the second is the extraordinary discovery of Abdeslam's hiding place. He was back in the Molenbeek suburb of Brussels where he grew up and was living only a few hundred meters from his family home. He was reportedly seen moving around the neighborhood, once going into a café. That it took Belgian security services some five months to pin him down suggests that the local community lived in fear of reprisals if they tipped off the authorities. For that fear to exist also means that there were other terrorists prepared to murder informers. And in retrospect, it will be clear that there was another indicator that could have pointed toward further immediate terror attacks. The Belgian authorities permitted Abdeslam's lawyer to say publicly that his client was collaborating with investigators. Though IS undoubtedly operates the classic cell structures in which very few terrorists have any knowledge of other cells, Abdeslam very probably knew something that would enable the authorities to track down some of his fellow killers. Therefore, with the threat of imminent exposure, cells that knew they might be vulnerable had the option of fleeing or bringing forward planned attacks. It appears that they took the latter option. None of this was rocket science. Yet the state of alert at Zaventem airport was clearly not high enough. Passengers reported seeing just two armed soldiers at the entrance to the departure area. This is, therefore, a major failure for Belgian intelligence and the Belgian government for which, when the dust clears, senior people must be held responsible.