The global economy suffered a new blow yesterday as Maersk, the world’s largest shipping company, announced that it would no longer put its tankers at the mercy of pirates off Somalia.

Maersk’s decision to stop plying the route through the perilous waters came as pirates on board the super-tanker Sirius Star issued a $25 million (£17 million) ransom demand, with a warning of “disastrous” consequences if the money were not paid.

Pressure is mounting for an international solution to the menace in and around the Gulf of Aden as world leaders urged shipping companies and their insurers not to embolden the buccaneers by giving in to ransom demands.

Arab leaders met in Egypt to discuss the crisis as Britain prepared to take charge of a European Union fleet of up to ten warships to complement the multinational force already operating along the Somali coast. In a rare show of unanimity, the UN Security Council adopted a British plan imposing fresh sanctions to freeze pirates’ assets and curb the illegal flow of weapons to Somalia.

AP Moller-Maersk said that it had decided to reroute its 50-strong oil tanker fleet via the Cape of Good Hope because it could no longer guarantee the safety of the slow-moving ships.The oil company BP is also examining new security measures. “We constantly monitor the security and safety of our ships,” said an official at BP, which operates 77 managed vessels and a further 115 under charter. “We are looking at suitable measures to protect them.”

Another British company, BG Group, which operates a fleet of four of its own and nine chartered vessels for the transport of liquefied natural gas, also said that it was reviewing the security of the areas in which it operates, which include the Gulf of Aden.

Shipping companies are aware that the threat now goes farther than the Gulf of Aden: the Sirius Star was on the Cape route when it was captured, close to the Seychelles, more than 400 nautical miles from the Somali coast.

The furore over piracy is pitting companies against governments, dragging in every seafaring country of the world. The Foreign Minister of Saudi Arabia, home to the Sirius Star’s state-owned operators, said yesterday that paying a ransom would only bolster piracy - a sentiment echoed by David Miliband, the Foreign Secretary.

“Payments for hostage-taking are only an encouragement to further hostage-taking,” Mr Miliband said in London, shortly before a meeting with Prince Saud al-Faisal. The Prince went further, hinting at his support for military action.

Two accounts of the pirates’ demands emerged yesterday - a purported audio recording of a pirate leader on board the Sirius Star, and a phone call from another pirate on the ship. “We are demanding $25 million from the Saudi owners of the tanker,” the man, Mohamed Said, told Agence France-Presse. “The Saudis have ten days to comply, otherwise we will take action that could be disastrous.”

The Qatar-based television channel al-Jazeera broadcast an audio tape featuring what it said was the voice of Farah Abd Jameh, a pirate on the tanker. “Negotiators are located on board the ship and on land,” he said. “Once they have agreed on the ransom it will be taken in cash to the oil tanker. We assure the safety of the ship that carries the ransom. We will mechanically count the money and we have machines that can detect fake money.”

The $25 million demand is the second-largest that Somali pirates have ever made. The captors of the Faina, a Ukrainian arms ship, demanded $30 million for the return of the crew and the cargo of 33 tanks and thousands of guns and ammunition.

Another vessel, meanwhile, was on its way home to Hong Kong yesterday after two months of captivity that ended in an undisclosed ransom payment. Sinotras Shipping confirmed that the Great Creation, a cargo ship carrying chemical fertilisers, and its 25-member crew, had been freed.

More than 250 people on board roughly 15 ships are still being held off the Somali coast.

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