The EU threatened to act against Iran last night if it did not immediately and unconditionally release the 15 British sailors and marines it has been holding for more than a week.
EU foreign ministers meeting in Bremen, Germany, threatened "appropriate measures" if Tehran did not let the group go, supporting Britain's position that the crew had been in Iraqi waters when they were seized eight days ago. The ministers did not spell out what measures would be taken, but British diplomats hoped they would involve an escalating array of punitive steps.
The tough statement was the kind of direct rebuke Britain had sought in vain from the UN security council on Thursday night when, in the face of resistance from Russia and others, the council only expressed concern but threatened no action. Despite the EU statement, prospects for a quick resolution to the crisis dwindled yesterday after another propaganda video and letter featuring more dubious confessions and apologies by the captives.
The only glimmer of hope for a quick diplomatic solution was a note presented yesterday to Britain's ambassador in Tehran, portrayed by Iranian officials as conciliatory, which bore some resemblance to a letter sent shortly before the end of a similar drama in 2004.
The letter restated that the British naval patrol was in Iranian waters when it was intercepted by boats of the Iranian revolutionary guard, which Britain denies. But unlike previous Iranian pronouncements it did not demand an apology, just a guarantee it would not happen again.
After the delivery of the letter, an Iranian official expressed hope to the Guardian that the crisis would be "resolved soon". But Margaret Beckett, the foreign secretary, dismissed it, saying it did not suggest Iran was looking for a way out.
Geoffrey Adams, the British ambassador to Tehran, returned to the foreign ministry with a reply last night, but the Foreign Office would not say what it was. British officials have diminishing confidence that the foreign ministry has any control over the guards who captured the British crew. "It's just white noise," said one diplomat about the Iranian note. "Our reaction over the weekend is that we're going to carry on our efforts, but we're not going to react to everything the Iranians do."
An Iranian official said the matter was being handled properly by the foreign ministry and the supreme national security council, and rejected suggestions that any other agencies were trying to influence the outcome. Downing Street is understood to take a rosier view of the note than the Foreign Office, believing it opened a clear channel of communication. Tony Blair stressed the need for calm in a statement, but he also expressed "disgust" at the captives' treatment.
The Iranian captors continued to use the only female captive, Leading Seaman Faye Turney, to broadcast anti-British messages. A third letter in her handwriting claimed she was being "sacrificed, due to the intervening policies of the Bush and Blair governments". "It is now our time to ask our government to make a change to its oppressive behaviour towards other people," the letter said.
Another captive, Nathan Summers, was also broadcast admitting the British crew had "trespassed without permission".
Responding to the broadcast of the latest video, Mr Blair told reporters in Manchester: "The Iranians have to realise if they continue in this way they will face increasing isolation - we had the UN statement yesterday, the EU today and will be talking to other key allies over the weekend."
Gordon Brown, speaking during a visit to British forces in Afghanistan, told reporters: "Overnight, the UN resolution is calling definitively for their release. That's the unanimous view of the international community."
Opposition politicians stressed the need for a unified front. David Cameron told the BBC: "I think the British government is doing the right thing. They have my support. "
Sir Menzies Campbell, the Liberal Democrat leader, stressed that it was impossible to see the full picture: "There's what's being done in public, what's being done in private and what's being done in private by intermediaries."
Interrogation
The captured sailors would not have had special "conduct after capture" training and will have to rely on common sense, military sources say. They would have been advised to say little about their families to avoid greater pressure. But formal training is usually reserved for special forces and pilots, who endure mock interrogations.
Military sources suggested the captives were unlikely to have any sensitive state secrets. "In the main, they should just use their common sense," said one official. Whether training for capture is reviewed as a result of this incident will depend on their eventual debriefing.
Richard Norton-Taylor