Saudi Arabia's intelligence community scored a major coup when one of its agents infiltrated an Al-Qaeda cell in Yemen. He was chosen by the group as a suicide bomber and given a new "underpants" bomb which it appears could pass normal security screening, because it contains no metal. This agent’s information also led to the killing in a US drone strike of a top Al-Qaeda planner.

Those are the published details of what this brave individual achieved. It must be that when he slipped away from the terrorists, he also took with him a great deal of vital information about the identity, procedures and organization of Al-Qaeda in Yemen, which is currently the most active part of the ruthless terrorist network.

It is easy to imagine the panic triggered by the agent’s escape. The terrorists are having to ask themselves what this man could have been told, and also found out for himself, about their operations, personnel, structures and plans. Virtually everything may have to be changed, codes will be scrapped, orders countermanded and warnings sent to terrorist cells that could well now be compromised.

These warning in themselves offer new penetration opportunities to Saudi and allied intelligence services. Advanced signals monitoring may be able to decode any enciphered messages, identify the location of the senders and perhaps also pinpoint where the receivers are as well.

And then there is probably a more lasting damage that has been done to the terrorists. They will be asking themselves who else might be a spy. Is anyone who was friendly with the Saudi agent, or who was recommended by him, are any of them spies? Sowing the seeds of suspicion and mistrust could well produce rancorous accusations, summary executions and internal power struggles, which will cripple Al-Qaeda in the Yemen for some time to come.

Such suppositions are entirely reasonable but so too is the unfortunate fact that this major victory in the Yemen has not destroyed terrorism in Arabia. We know from a steady flow of news reports that here in the Kingdom, terrorists suspects are still being picked up, tried in the Specialized Criminal Court and many of them convicted.

It is a testament to the effectiveness of the Saudi intelligence community that there have been no major terrorist attacks here in recent years. The vigilance of the authorities, coupled with the heightened sense of public awareness since 2007, has meant that it has become far more difficult for terrorist cells to function here. Ordinary people have looked around their neighborhoods and contacted the police when they spot something strange or out of the ordinary, such as new arrivals who prefer to stay indoors during the day and only tend to go out or receive visitors during the night.

This outstanding achievement however has not led to any complacency on behalf of the security forces. Hopefully the general public is also still on the alert, though it is understandable that with no major attack for three years, they may feel more relaxed about the terrorist threat.

The Yemen terrorist cell so brilliantly disrupted by the Saudi agent, was planning to blow up a US-bound plane on May 1, to mark the first anniversary of the death of Osama Bin Laden. But the men of violence have many more anniversaries of their defeats to celebrate with a new act of outrage. They need no excuse to kill and maim in their bigoted, false and repugnant claim to be acting in the name of Islam.

The war against terror will go on, until the last poor dupe has blown himself up or the last Al-Qaeda leader is hunted down. There is also, tragically, an unknown number of tears and howls of grief that must come from decent people caught up in this wickedness of these evil men. Nevertheless, the outcome cannot be in doubt. Good will triumph over evil and the world will one day be rid of this scourge.