Basking in the derring-do of France's elite naval commando force, President Sarkozy yesterday warned criminals on the high seas that France would take whatever military measures were needed to stamp out the resurgence of the old crime of piracy. His warning came after navy frogmen stormed a captured yacht off Somalia and rescued a French couple for whom a ransom of $1.4 million had been demanded.

President Sarkozy, who supervised the operation personally, called on other nations to join France in ridding the troubled waters of pirates who have hijacked more than 50 ships this year and made the shipping lanes in the Gulf of Aden the most dangerous in the world.

About 48,000 vessels pass through these waters each year. The terrorists who lie in wait, picking off yachts, freighters and fully laden tankers, are very different from the old pirate image. Armed with missiles and rockets, they have established a haven in northern Somalia, and send out speedboats to seize ships and crews for ransom. The attacks are often co-ordinated from a captured vessel disguised to look harmless.

As Somalia, a country without a functioning government for the past 17 years, sinks ever deeper into poverty, violence and lawlessness, the attacks have grown in number and daring, becoming a main source of income for the gangs terrorising the country. Fifteen ships are being held in the pirate base at Eyl. Ransom demands for about 150 hostages of all nationalities, some there for months, have risen steeply. On Sunday rockets were fired at a French fishing fleet in the Indian Ocean, 400 miles off the Somali coast. And only hours after the French couple were rescued, pirates attacked a Hong Kong-registered chemical tanker and took hostage its crew of 22.

This is the second rescue operation France has mounted in the past six months. But the maritime threat concerns all seafaring nations. As Mr Sarkozy remarked, this is a fully fledged criminal industry that endangers fundamental rights, freedom of movement and international trade. Warships from Britain, the US and its allies have been patrolling the region for the past eight years, but have been unable or unwilling to pursue the terrorists to their strongholds. The UN Security Council has authorised warships to enter Somali waters to combat piracy, and on Monday European ministers, in response to calls by France and Spain, agreed to set up a unit to co-ordinate the fight against this terrorism at sea. Armies are learning how to fight asymmetric wars against guerrillas and terrorists. Navies, plainly, have to do the same.

More is clearly needed. The law of the sea allows any nation to take robust measures to protect its shipping. Bold operations to rescue hostages, as President Uribe found in Colombia, bring swift popularity boosts. The danger, however is that sooner or later a politician will push the button on a mission to liberate those held captive and it will end in anything but glory.

Little can be done without tackling the source of this menace: the poverty and chaos in Somalia, whose festering problems engender crime, violence and religious extremism. Piracy is even hampering UN efforts to feed the country's starving. This failed state is a spectacular example of the dangers of global neglect. Unless Somalia is rescued from this hell, the world will pay dearly.