The pirates would hardly have been able to believe their eyes as they inspected the hold of their latest conquest, the Faina.

The Ukrainian vessel was heading for the Kenyan port of Mombasa loaded down with rocket-propelled grenades, anti-aircraft guns and 30 Russian T-72 tanks.

“They really hit the jackpot this time,” said a regional arms expert. “There is not much they can do with the tanks, but the RPGs and the Zu-23 anti-aircraft guns will soon find their way into Somalia’s arms markets.

“These are the sort of weapons that fighters in Somalia really like.”

Almost 60 vessels have been attacked this year as armed gangs of pirates plunder the seas off Somalia.

Its 2,300-mile coastline offers rich pickings for the modern-day buccaneers, who use AK-47s and RPGs rather than the cutlasses and flintlock pistols of romantic imagination.

In a country already awash with weapons, yesterday’s haul will only worsen a bloody conflict that has escalated in the past month as Islamist insurgents battle government troops and their Ethiopian allies.

An international coalition of navies has so far failed to stem the trade, which brings in as much as $1.5 million (£800,000) per ship.

The Ukrainian foreign ministry said today that the Faina’s captain had radioed maritime authorities to say that three cutters with armed men were approaching his vessel at high speed before communications were lost. Her cargo was destined for South Sudan’s government.

It brings the number of ships held by the buccaneers to 14, with 300 crew members held hostage.

They are being held around the tiny fishing village of Eyl in Puntland, a semi-autonomous region of Somalia.

At times it seems as if the pirates can act with impunity. Earlier this week the Danish navy freed 10 pirates it had captured at sea, saying they had insufficient evidence to prosecute them.

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