Britain will not pay a ransom for two Britons being held by pirates who hijacked a super-tanker off the east African coast, the Foreign Secretary said today.

David Miliband said that paying for the release of Peter French, the ship's chief engineer, and James Grady, the second officer, risked encouraging more piracy.

The Foreign Office has confirmed that Mr French and Mr Grady are among the 25 crew taken hostage at the weekend aboard the giant carrier Sirius Star, which was seized off the coast of Kenya carrying two million barrels of oil worth $100 million.

The hijackers revealed earlier that they are seeking $25 million in ransom from the ship's Saudi owners, and have given a deadline of ten days for the cash to be handed over. They hinted at unpleasant consequences if the money was not paid.

"There is a strong view of the British Government, and actually the international community, that payments for hostage-taking are only an encouragement to further hostage-taking," said Mr Miliband.

“We will be approaching this issue in a very delicate way, in a way that puts the security and safety of the hostages to the fore.”

Britain's official line on how to tackle the pirates comes as a marked contrast to that of France, which has twice this year sent marine commandos on missions to rescue French nationals taken hostage by pirates in the lawless waters off the Horn of Africa.

The Britons worked on the super-tanker alongside 19 crew from the Philippines, two from Poland, one Croatian and one Saudi.

"The families of Peter French, from County Durham, and James Grady, from Strathclyde, greatly appreciate the concern that has been expressed by people throughout the UK and beyond, about Peter and James. They hope that Peter and James will be home safely to their families very soon," said the families of the two Britons, in a statement issued through the Foreign Office last night. Mr French is married and has a 17-year-old daughter.

“We are demanding $25 million from the Saudi owners of the tanker,” said Mohamed Said, one of the pirates, in a phone interview from the ship anchored off the Somali coast.

“We do not want long-term discussions to resolve the matter. The Saudis have 10 days to comply, otherwise we will take action that could be disastrous.”

Mr Miliband said that a European force should deploy to the Gulf of Aden, in support of a NATO armada that is already patrolling off the coast of Somalia.

“It is very important that the international community stands firm against the scourge of hostage-taking, whether it is on boats, whether it is on airlines, or elsewhere," he said.

“All of our hearts go out to all of those people who are now hostages on that ship, obviously in our case especially for the two British hostages. Their families will be going through a wrenching hell of waiting.

“It is important we assure them we are fully engaged with all of our partners on this issue.

“There is a fundamental problem in the Gulf of Aden. That is why the deployment of the European force is the right thing to do.”

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• 'Was it real?' The US bailout nightmare
• Iranian opposition plays the long game