Hardly a week goes by these days without news of yet another vessel being hijacked by Somali pirates in the Gulf of Aden. On Tuesday, a chemical tanker with 23 Filipino crew was taken hostage. Last week, a Danish ship with 13 people on board was overrun. The week before that, a Turkish bulk carrier was hijacked en route from Canada to Asia. The roll-call of attacks and hostage-taking off the Horn of Africa is a cause for alarm.

Piracy, of course, is hardly a new phenomenon. Criminal gangs have been exacting treasure on the high seas for centuries. But the lawlessness off Somalia – in one of the world’s busiest shipping lanes – needs to be stopped by concerted international action. This is not just because of the scale of the problem, with some 83 ships coming under attack this year. There is also evidence that shipowners and insurers, which have this year paid out $20m in ransoms, are avoiding the region. Last week, a big shipping company became the first to confirm it is re-routing all vessels around the Cape of Good Hope, rather than transiting the Suez canal. This makes the distance from the Middle East to the US some 30 per cent longer, adding to the cost of oil and commodities.