Two vessels, light arms and Global Positioning System (GPS) devices are among items that Tehran has kept, the news agency Fars, run by the Office of Irans Supreme Leader Ayatollah Ali Khamenei, quoted an informed source as saying earlier this week.
The eight sailors and seven marines were detained by Iranian Revolutionary Guards while conducting a routine early morning anti-smuggling check on a merchant vessel in the Gulf on March 23.
The Britons were released nearly two weeks later after they were forced to apologise on state television for illegally entering Iranian waters. Upon returning to the UK, all 15 servicemen denied they had entered Iranian waters.
Some analysts believe that Londons weak response to the capture of its sailors has emboldened Irans theocratic government to up the ante in order to force British and U.S. troops to scale down their operations against Iranian agents believed to be in Iraq.
The sailors capture mirrors a similar incident in June 2004, when Irans Revolutionary Guards seized six British marines and two sailors along with their gunboats, claiming that they had strayed into Iranian waters. They were held in Iranian custody for three days.
The 8 Britons were blind-folded and paraded on television.
Then-British Defence Secretary Geoff Hoon later told the House of Commons that the released sailors accounts showed that they had been abducted by the Revolutionary Guards while they were still in Iraqi waters. The sailors also revealed that while in captivity, they had been forced into a shallow ditch, blindfolded, and led to believe that they would be shot dead.
The British Foreign Office however dismissed such claims and then-Foreign Secretary Jack Straw warmly thanked his Iranian counterpart Kamal Kharrazi after the servicemens release, and said the sailors had been well-treated, even though they had been paraded in front of television cameras in clear violation of the Geneva Conventions.
Despite repeated demands by London, Tehran never returned the three Royal Navy gunboats. In 2005, they were put on display in a town near where they had been seized.