The dispute over just where the British sailors were at the time of their capture will probably never be resolved to everyone's satisfaction, because they were captured offshore of a region of the Iraqi-Iranian border where the demarcation line itself is subject to much disagreement.
That region is the Shatt Al-Arab waterway, a narrow channel where the Tigris and Euphrates rivers jointly flow into the Persian Gulf. The Shatt Al-Arab -- and the sea boundary offshore -- has long been used as a bargaining chip between Iran and Iraq and even as a cause of war.
In 1980, then-Iraqi President Saddam Hussein dramatically ripped up on television a 1975 treaty establishing the middle of the river as the frontier. Iraq and Iran then fought an eight-year war that never ended in a peace treaty.
Still, international maritime authorities widely accept the 1975 treaty as still standing and have drawn an imaginary line out to sea from the midpoint of the channel to serve as a sea boundary until the issue is one day decided.
unjustified and wrong. As such it is a matter of deep concern to us."
Britain argues that its sailors and marines from the British frigate "HMS Cornwall" were seized well to the west -- that is, the Iraqi side -- of this line.
"My primary message is clear: 'HMS Cornwall' with her boarding party was about her legal business, in Iraqi territorial waters, under a United Nations Security Council resolution and with the explicit approval of the Iraqi government," Royal Navy Vice Admiral Charles Style, deputy chief of the British defense staff, told reporters on March 28 in London.
"The action by Iranian forces in arresting and detaining our people is unjustified and wrong. As such it is a matter of deep concern to us," Style added.
The 15 British naval personnel were seized after they left the "HMS Cornwall" aboard rubber patrol boats to conduct a routine antismuggling check on a commercial freighter. One of the rubber boats had a Global Positioning System (GPS) plotter aboard that communicated the two boats' positions to the "HMS Cornwall" at all times.
But Iran argues that the plotter on the seized boat registered a different location than the one presented by Britain. That has prompted a back-and-forth argument.
When Iran presented the first location it claims the plotter showed, London informed Tehran that this location was also in waters widely accepted to be Iraqi.
Tehran then provided what it called a "corrected" rereading of the rubber boat's location plotter. It then claimed the rubber boat was actually at a second location 1 nautical mile (1.9 kilometers) from the first Iranian-given position and thus clearly in Iranian waters.
As the two countries publicly exchange evidence based on high-tech locators whose functions most people poorly understand, they also are waging a hearts-and-minds battle based on what the sailors themselves say.
Tehran is relying heavily in this propaganda war on what it says are voluntary confessions that the captives trespassed into Iranian territory.
"Yes, I'd like to say to the Iranian people I can understand why you are so angry about our intrusion into your waters," British Lieutenant Felix Carmen said in video aired on April 1 on Iranian state television.
Two other Britons have also appeared on television. In addition to expressing regret for what they say is trespass, they have also praised their captors for treating them well.
"Obviously we trespassed into their waters," Faye Turney, the only woman crew member, said in a video aired on March 28. "They were very friendly, very hospitable, very thoughtful, nice people. They explained to us why we'd been arrested. There was no aggression, no hurt, no harm. They were very, very compassionate."
Style Vs. Substance
All this takes the propaganda war to a level where arguments citing satellite data from the cold world of machines confronts the emotional, human testimony of the captives themselves.
Iran has sought to direct the argument primarily to listeners in the Arab world, particularly in Iraq. It has done so by first airing the British captives' remarks on its Arabic-language foreign broadcasting channels, particularly Al-Alam television.
Britain has countered in this battle of emotions by saying Iran is abusing the captives by parading them on television and forcing them to say untruths.
So far, there is no evidence that the audience will find the human evidence presented by Iran more convincing than the machine evidence presented by Britain. But the confrontation appears to highlight at least some of the cultural differences between the technology-based West and the more traditional East.
War By Proxy?
What remains unclear are the precise motives for Iran's Revolutionary Guards seizing the British personnel when they were on a peaceful assignment. The "HMS Cornwall" is part of a task force that operates under UN Security Council authority to catch smugglers in Iraqi waters.
But the seizure comes at a time of high tension between Iran and the West -- and the UN Security Council -- over Iran's nuclear program. It largely coincided with a Security Council vote to expand sanctions against Iran for refusing to halt uranium enrichment.
At the same time, Iran is at odds with London and Washington over charges that Iran supplies money and expertise to militants attacking coalition troops in Iraq.
And Iran is angry over the seizure by U.S. forces of five Iranians in northern Iraq in January. Tehran says the five were diplomats but Washington says they were part of a network of Iranian agents helping anticoalition militants.
Whatever the motives for the seizure of the Britons, there are suggestions Iran wants a deal.
Tehran demands a formal apology from London for what it says was trespass into its territory. But U.S. officials have suggested they think larger demands might be in the offing. Washington has already ruled out any exchange of the British naval personnel for the five Iranians taken in Iraq.
The crisis over the British captives has already run longer than a similar showdown in 2004. In June of that year, six British marines and two sailors were seized by Iran in the Shatt Al-Arab waterway.
They were released unharmed three days later after saying they had entered Iranian waters illegally.
RFE/RL Iran Report
SUBSCRIBE For regular news and analysis on Iran by e-mail, subscribe to "RFE/RL Iran Report."