On 27 August a suicide bomber called Abdullah Hassan Tali Asiri nearly killed the Deputy Saudi Interior Minister, Prince Muhammed bin Nayif. The Prince received minor injuries; the bomber was blown in half. Several aspects of this under-reported incident are noteworthy.The Saudi bomber came from Yemen, ostensibly to surrender himself in person to the Prince, who has made considerable efforts to rehabilitate former jihadis. It is interesting that Yemen has beome a safe haven for jihadists after Saudi Arabia has become more uncongenial in recent years.

While AQ has certainly practiced assassination in the past - for example Ahmad Shah Masud a few days before 9/11 - it has not struck directly at a member of the Saudi royal family, preferring major attacks on compunds for foreign technicians or oil installations. This may reflect their logistical difficulties in mounting that sort of attack.

Finally, the assassin was only admitted to the Prince after undergoing four physical searches. Although it has not been widely reported, except by the BBC's excellent Frank Gardner, the forensic reports on what was left of Asiri indicate that his bomb was inside him, and that a mobile phone call probably detonated it.

This resort to surgically-implanted explosive devices has very worrying implications for current airport security measures, or indeed the technologies used to detect bombs used in a wide variety of public buildings. The fertility of evil should no longer amaze us.